UniSR San Raffaele Test Practice Paper with Answers (2027)

Section	Questions	Time	Marks (International MD Program Admission Test)
International MD Program Admission Test	60	80 min	+1 correct, -0.3 wrong, 0 blank

Question 1

Logic, Problem Solving & Reading Comprehension · Formal Logic · Foundation

"All the trains to Milan left on time this morning."

Which one of the following is the negation of this statement?

Show answer and explanation

Answer: D

To deny that every train left on time, it is enough for a single train not to have done so, so the negation of "all are" is "at least one is not". "No train left on time" and "all left late" are far stronger claims that could both be false while the original is false too. "Most left late" says too much, and "some left on time" is compatible with the original statement rather than contradicting it.

Question 2

Logic, Problem Solving & Reading Comprehension · Verbal Logic · Foundation

INSOMNIA is to SLEEP as:

Show answer and explanation

Answer: A

Insomnia is a lack of sleep, and famine is a lack of food. Fatigue is a result of exercise, not an absence of it; a fever is too high a temperature, not a missing one; a glutton has too much appetite; and a library contains books. Only famine and food share the relationship of absence.

Question 3

Logic, Problem Solving & Reading Comprehension · Problem Solving · Foundation

Marta is three times as old as her son. In 12 years' time she will be twice as old as he will be then.

How old is Marta now?

Show answer and explanation

Answer: C

Let the son be s, so Marta is 3s. In 12 years: 3s + 12 = 2(s + 12), so 3s + 12 = 2s + 24 and s = 12. Marta is 3 × 12 = 36 (check: in 12 years she is 48 and he is 24). 48 is her age in 12 years' time, and 24 is twice the son's present age, not Marta's.

Question 4

Logic, Problem Solving & Reading Comprehension · Set and Diagram Logic · Foundation

In a class of 30 students, 18 study French, 14 study German and 5 study neither language.

How many students study both French and German?

Show answer and explanation

Answer: E

30 − 5 = 25 students study at least one language. Adding the two groups gives 18 + 14 = 32, which counts the students who study both twice, so both = 32 − 25 = 7. Answering 2 (32 − 30) forgets the 5 who study neither.

Question 5

Logic, Problem Solving & Reading Comprehension · Formal Logic · Standard

A clinic's rule states: "A patient may book a scan only if they have a referral letter."

If the rule is followed, which one of the following must be true?

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Answer: B

"Only if" introduces a necessary condition: booking a scan requires a referral letter, so a patient without one cannot book (the contrapositive). The rule does not say a letter is sufficient, so the first and last options reverse it. The option about patients who may not book also reverses it, and nothing in the rule tells us whether some letter-holders are refused, so that option is not guaranteed either.

Question 6

Logic, Problem Solving & Reading Comprehension · Verbal Logic · Standard

A town introduced a 30 km/h speed limit throughout its centre at the start of 2024. In 2025, the number of pedestrians injured in road accidents in the centre was 25% lower than in 2023. The council concludes that the lower speed limit has made the centre's roads safer for pedestrians.

Which one of the following, if true, most weakens the council's conclusion?

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Answer: D

The ring road offers a different explanation for the fall: with half as much traffic, fewer pedestrians would be hit whatever the speed limit, so the data no longer point to the limit. The neighbouring town's rise supports the council. Residents' opinions and the ages of the injured have no bearing on what caused the fall, and a similar fall for cyclists fits the speed-limit explanation as well as any other.

Question 7

Logic, Problem Solving & Reading Comprehension · Problem Solving · Standard

Five patients, P, Q, R, S and T, are seen by a doctor one at a time, in positions 1 to 5.

R is seen immediately after P. T is seen before Q, but T is not seen first. S is seen third.

Which patient is seen fifth?

Show answer and explanation

Answer: A

With S in position 3, the pair P then R must take positions 1–2 or 4–5. If P and R take 4–5, then T and Q fill positions 1–2 with T first, which is not allowed. So P is 1 and R is 2, leaving T and Q for 4 and 5; T comes before Q, so the order is P, R, S, T, Q and Q is fifth. This is the only arrangement that meets all three conditions.

Question 8

Logic, Problem Solving & Reading Comprehension · Formal Logic · Standard

Every member of the rowing club can swim. No one who can swim is afraid of water. Some members of the chess club are afraid of water.

Which one of the following must be true?

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Answer: C

The chess club members who are afraid of water cannot be swimmers, because no swimmer is afraid of water, so at least some chess club members cannot swim. Nothing is said about chess club members who are not afraid of water: they might swim and might row, so "no chess member rows" and "no chess member swims" go too far, and an overlap between the clubs is possible but not certain. "Everyone who can swim rows" reverses the first premise.

Question 9

Logic, Problem Solving & Reading Comprehension · Set and Diagram Logic · Standard

100 medical students were asked whether they run, cycle or swim. 45 run, 40 cycle and 35 swim. 15 both run and cycle, 12 both run and swim, and 10 both cycle and swim; each of these three figures includes the 5 students who do all three activities.

How many students do exactly one of the three activities?

Show answer and explanation

Answer: E

Run only: 45 − 15 − 12 + 5 = 23. Cycle only: 40 − 15 − 10 + 5 = 20. Swim only: 35 − 12 − 10 + 5 = 18. Exactly one: 23 + 20 + 18 = 61. Forgetting to add back the 5 who do all three (they are removed twice) gives 46, and 83 is the number who do at least one activity (88) less the 5 who do all three, which still includes those who do exactly two.

Question 10

Logic, Problem Solving & Reading Comprehension · Verbal Logic · Standard

"Lucia cannot have written the anonymous letter to the newspaper. The letter was typed, and Lucia owns neither a typewriter nor a computer."

Which one of the following is an assumption on which this argument depends?

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Answer: B

The argument moves from "Lucia owns no typing machine" to "Lucia could not have typed the letter". That step holds only if she could not have used someone else's machine, at a library, a friend's house or work. The newspaper's policy and Lucia's motives play no part in the reasoning, and the argument needs no claim about who else could have written it or whether the typist owned the machine used.

Question 11

Logic, Problem Solving & Reading Comprehension · Problem Solving · Standard

Pump A on its own fills a tank in 6 hours. Pumps A and B working together fill the same tank in 2 hours. Starting with the tank empty, both pumps are switched on; after 1 hour pump A breaks down, and pump B carries on alone until the tank is full.

How long does it take, from the start, to fill the tank?

Show answer and explanation

Answer: D

Together the pumps fill 1/2 of the tank per hour, and A fills 1/6, so B fills 1/2 − 1/6 = 1/3 per hour. After 1 hour together the tank is half full; B fills the remaining 1/2 in (1/2) ÷ (1/3) = 1.5 hours. The total is 1 + 1.5 = 2.5 hours. 2 hours assumes A never breaks down, and 4 hours adds B's full 3 hours to the first hour.

Question 12

Logic, Problem Solving & Reading Comprehension · Formal Logic · Standard

If a blood sample is contaminated, the test result will be positive. If the test result is positive, the patient will be retested.

The patient was not retested. Which one of the following follows?

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Answer: A

The two rules chain together: contaminated → positive → retested. Since the patient was not retested, the result cannot have been positive, and so the sample cannot have been contaminated. That is a definite conclusion, so "nothing can be concluded" is wrong, and a positive result or contamination would each have led to a retest. The last option denies the condition rather than the result: a clean sample could still give a positive result for another reason.

Question 13

Logic, Problem Solving & Reading Comprehension · Verbal Logic · Foundation

Vitamin D is made in the skin when it is exposed to sunlight. In northern countries the winter sun is too weak for the skin to make much vitamin D, and few foods contain it naturally. For this reason, many doctors in these countries recommend a vitamin D supplement during the winter months.

Which one of the following conclusions is best supported by the passage?

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Answer: C

The passage gives two reasons for low winter intake (weak sun, few food sources), which is why a supplement is recommended; the cautious conclusion follows directly. It does not say everyone is deficient, that the skin makes none outside summer, or that supplements beat sunlight. It says nothing at all about southern countries.

Question 14

Logic, Problem Solving & Reading Comprehension · Problem Solving · Standard

A committee of 3 people is to be chosen from 4 doctors and 3 nurses. The committee must include at least one nurse.

How many different committees are possible?

Show answer and explanation

Answer: E

Without restriction there are 7C3 = (7 × 6 × 5) ÷ (3 × 2 × 1) = 35 committees. Those with no nurse are all-doctor committees: 4C3 = 4. So 35 − 4 = 31 include at least one nurse. 18 counts only committees with exactly one nurse (3 × 6), and 45 (3 × 6C2) counts committees with two or three nurses more than once.

Question 15

Logic, Problem Solving & Reading Comprehension · Formal Logic · Challenging

"The clinical trial will not go ahead unless both the funding and the ethics approval are confirmed."

If this statement is true, which one of the following must also be true?

Show answer and explanation

Answer: B

"Not X unless Y" means X only if Y: the trial goes ahead only if funding and approval are both confirmed. So missing either one, including the ethics approval, stops the trial. The statement gives necessary conditions, not sufficient ones, so the first option reverses it. The remaining three all reason backwards from the trial not going ahead, which could happen for some other reason even with both confirmed.

Question 16

Logic, Problem Solving & Reading Comprehension · Set and Diagram Logic · Challenging

In a group of 40 students, 28 passed biology, 25 passed chemistry and 30 passed physics.

What is the smallest possible number of students who passed all three subjects?

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Answer: C

Count the failures instead: 12 failed biology, 15 failed chemistry and 10 failed physics, 37 failures in all. Even if no student failed more than one subject, at most 37 students failed something, so at least 40 − 37 = 3 passed everything, and 3 is achievable with the failures kept separate. 0 ignores this, 13 is the minimum overlap of biology and chemistry alone, and 25 is the maximum, not the minimum.

Question 17

Logic, Problem Solving & Reading Comprehension · Verbal Logic · Challenging

In a study of 500 runners, those who stretched before every run reported fewer injuries than those who did not. However, the runners who stretched were also, on average, ten years younger. Clearly, then, it is age and not stretching that explains the difference, so stretching does nothing to prevent injury.

Which one of the following best describes the flaw in this argument?

Show answer and explanation

Answer: A

The age difference shows that the study cannot isolate the effect of stretching, but both age and stretching could contribute. Jumping from "age might explain it" to "stretching does nothing" is the flaw. 500 runners is not a tiny sample, the argument says nothing about severity or about how injuries were reported, and it claims only that stretching does not help, not that it does harm.

Question 18

Logic, Problem Solving & Reading Comprehension · Problem Solving · Challenging

Six lectures, Anatomy, Biochemistry, Chemistry, Genetics, Physiology and Statistics, are given one per day from Monday to Saturday.

Statistics is on Wednesday. Genetics is on the day immediately after Biochemistry. Physiology is exactly two days after Anatomy. Chemistry is on a later day than Genetics.

Which lecture is on Friday?

Show answer and explanation

Answer: D

The free days are Mon, Tue, Thu, Fri and Sat. Anatomy and Physiology two days apart must be Tue–Thu or Thu–Sat (Mon–Wed and Wed–Fri use Wednesday). Biochemistry then Genetics needs two consecutive free days: Mon–Tue, Thu–Fri or Fri–Sat. Thu–Fri leaves no room for Anatomy and Physiology; Fri–Sat forces Anatomy–Physiology onto Tue–Thu and Chemistry onto Monday, before Genetics, which is not allowed. So Biochemistry is Monday, Genetics Tuesday, Anatomy Thursday, Physiology Saturday and Chemistry Friday.

Question 19

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Foundation

Which one of the following best expresses the main idea of the passage?

Show answer and explanation

Answer: C

The passage follows Semmelweis from the comparison of the two clinics, through the handwashing order and its result, to the resistance that lasted until Pasteur and Lister supplied a theory: that is the whole arc. Crowding is explicitly ruled out (the second clinic was more crowded), so the first option is wrong. The passage never compares the skill of midwives and doctors, nor says Pasteur and Lister deserve the credit. Slow publication is one reason among several, so 'only because' is too strong.

Question 20

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Standard

Show the passage · Clean hands

In the 1840s the Vienna General Hospital ran two maternity clinics side by side. Women were admitted to them on alternate days, so the two clinics served very similar patients. Yet the death rate from puerperal fever, an infection that could follow childbirth, was far higher in the first clinic than in the second; in some years the first clinic lost around one mother in ten. The difference was so widely known that some women gave birth in the street rather than be admitted on the first clinic's day.

Ignaz Semmelweis, a young Hungarian doctor working in the first clinic, set out to find the cause. He ruled out explanations one by one. Crowding could not explain it, since the second clinic was the more crowded of the two. Nor could the women's backgrounds, which were alike in both. The one clear difference was the staff: the first clinic trained doctors and medical students, who also dissected bodies in the hospital's mortuary, while the second trained midwives, who did not.

The decisive clue came in 1847, when a colleague died after his finger was cut by a student's knife during a post-mortem examination. His illness closely resembled the fever that was killing the mothers. Semmelweis concluded that the students were carrying what he called cadaverous particles from the dissecting room to the women they examined. He ordered everyone entering the ward to wash their hands in a solution of chlorinated lime, and within months the first clinic's death rate had fallen to about the level of the second.

It would be pleasing to report that his colleagues were persuaded. Many were not. Semmelweis could show that washing worked but could not explain why, and his account of invisible particles struck many physicians as little better than a guess. He was also slow to publish, and when he did, his tone was bitter. Only later in the century, when the work of Louis Pasteur and Joseph Lister established that particular microbes cause particular infections, did his practice gain a theory that others could accept. His story is often told as one of genius ignored. It is also a reminder that evidence that something works rarely wins acceptance on its own when no one can say how it works.

What can most reasonably be inferred from the passage about the staff of the second clinic?

Show answer and explanation

Answer: A

The second paragraph says the midwives of the second clinic did not dissect bodies, and the third says Semmelweis traced the fever to particles carried from the dissecting room, so the midwives were less likely to carry that material. The second clinic was the more crowded, which rules out 'fewer women at a time'. Nothing in the passage says the midwives washed in chlorinated lime earlier, suspected hands themselves, or were less skilled.

Question 21

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Foundation

Show the passage · Clean hands

In the 1840s the Vienna General Hospital ran two maternity clinics side by side. Women were admitted to them on alternate days, so the two clinics served very similar patients. Yet the death rate from puerperal fever, an infection that could follow childbirth, was far higher in the first clinic than in the second; in some years the first clinic lost around one mother in ten. The difference was so widely known that some women gave birth in the street rather than be admitted on the first clinic's day.

Ignaz Semmelweis, a young Hungarian doctor working in the first clinic, set out to find the cause. He ruled out explanations one by one. Crowding could not explain it, since the second clinic was the more crowded of the two. Nor could the women's backgrounds, which were alike in both. The one clear difference was the staff: the first clinic trained doctors and medical students, who also dissected bodies in the hospital's mortuary, while the second trained midwives, who did not.

The decisive clue came in 1847, when a colleague died after his finger was cut by a student's knife during a post-mortem examination. His illness closely resembled the fever that was killing the mothers. Semmelweis concluded that the students were carrying what he called cadaverous particles from the dissecting room to the women they examined. He ordered everyone entering the ward to wash their hands in a solution of chlorinated lime, and within months the first clinic's death rate had fallen to about the level of the second.

It would be pleasing to report that his colleagues were persuaded. Many were not. Semmelweis could show that washing worked but could not explain why, and his account of invisible particles struck many physicians as little better than a guess. He was also slow to publish, and when he did, his tone was bitter. Only later in the century, when the work of Louis Pasteur and Joseph Lister established that particular microbes cause particular infections, did his practice gain a theory that others could accept. His story is often told as one of genius ignored. It is also a reminder that evidence that something works rarely wins acceptance on its own when no one can say how it works.

As it is used in the passage ('The decisive clue came in 1847'), the word 'decisive' most nearly means:

Show answer and explanation

Answer: D

The colleague's death is the clue that led Semmelweis to his conclusion about cadaverous particles: it settled what he had been trying to find out. 'Firmly expressed' is the sense used of people ('a decisive manager'), not of clues. The passage does not present the clue as the most recent, as surprising, or as widely reported.

Question 22

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Challenging

Show the passage · Clean hands

In the 1840s the Vienna General Hospital ran two maternity clinics side by side. Women were admitted to them on alternate days, so the two clinics served very similar patients. Yet the death rate from puerperal fever, an infection that could follow childbirth, was far higher in the first clinic than in the second; in some years the first clinic lost around one mother in ten. The difference was so widely known that some women gave birth in the street rather than be admitted on the first clinic's day.

Ignaz Semmelweis, a young Hungarian doctor working in the first clinic, set out to find the cause. He ruled out explanations one by one. Crowding could not explain it, since the second clinic was the more crowded of the two. Nor could the women's backgrounds, which were alike in both. The one clear difference was the staff: the first clinic trained doctors and medical students, who also dissected bodies in the hospital's mortuary, while the second trained midwives, who did not.

The decisive clue came in 1847, when a colleague died after his finger was cut by a student's knife during a post-mortem examination. His illness closely resembled the fever that was killing the mothers. Semmelweis concluded that the students were carrying what he called cadaverous particles from the dissecting room to the women they examined. He ordered everyone entering the ward to wash their hands in a solution of chlorinated lime, and within months the first clinic's death rate had fallen to about the level of the second.

It would be pleasing to report that his colleagues were persuaded. Many were not. Semmelweis could show that washing worked but could not explain why, and his account of invisible particles struck many physicians as little better than a guess. He was also slow to publish, and when he did, his tone was bitter. Only later in the century, when the work of Louis Pasteur and Joseph Lister established that particular microbes cause particular infections, did his practice gain a theory that others could accept. His story is often told as one of genius ignored. It is also a reminder that evidence that something works rarely wins acceptance on its own when no one can say how it works.

Which one of the following best describes the author's attitude to the resistance Semmelweis met?

Show answer and explanation

Answer: B

'It would be pleasing to report that his colleagues were persuaded' shows regret, while the last sentence offers a reason the resistance is understandable: evidence that something works rarely wins acceptance when no one can say how it works. The author never says the rejection was right, so 'fully justified' goes too far. Jealousy is not mentioned, the author treats the doctors' doubts as a real difficulty rather than indifference to evidence, and slow publication is listed as one factor, not as the one that would have changed the outcome.

Question 23

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Standard

Which one of the following best expresses the main point of the final paragraph?

Show answer and explanation

Answer: E

The paragraph's own summary is its last sentence: the railways created a need for agreement, while the form of the agreement was settled by people arguing. The first option says the opposite ('the railway did not decide the answer'), and the third generalises the very view the author is qualifying. The United States is an example of a different choice, not a better one, and pride is only one of three things people argued over.

Question 24

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Foundation

Show the passage · Railway time

For most of history, time was local. A town set its clocks by the sun, calling it noon when the sun stood highest in its own sky. Because the sun appears to cross the sky from east to west, noon arrives a little later at each step westward: in Britain, Bristol's noon falls about ten minutes after London's. As long as travel was slow, nobody minded. A coach journey from London to Bristol took most of a day, and a traveller whose watch was ten minutes out by the local clock on arrival hardly noticed.

The railways changed this. A timetable has to say when a train will leave each station, and a timetable that used a different time at every stop was an invitation to confusion and, on lines where trains in both directions shared a single track, to collisions. In 1840 the Great Western Railway began running all its trains on London time, and within a decade most British railway companies had followed. Station clocks showed 'railway time', even where the town hall clock nearby still showed local time.

For some years many towns lived with two times at once. Bristol's Corn Exchange clock was given a second minute hand so that it could show both. Some townspeople resented being told when noon was by a company in London, and a few councils held out for years. But the practical case was hard to resist: the post, the telegraph and the newspapers increasingly ran to the railway's clock, and a town that kept its own time made itself awkward to deal with. In 1880 Parliament made Greenwich Mean Time the legal time throughout Great Britain.

The change is usually told as a story of technology, and the railways certainly forced the question. Yet the railway did not decide the answer. A country could have chosen one national time, several zones or none at all, and countries chose differently: in the United States, far wider than Britain, the railway companies divided the country into several zones in 1883 rather than adopt a single time. What the railways created was a need for agreement; the form the agreement took was settled by people arguing over convenience, pride and who should be in charge.

According to the passage, why did differences in local time cause little difficulty before the railways?

Show answer and explanation

Answer: B

The first paragraph says 'As long as travel was slow, nobody minded', and gives the day-long coach journey on which ten minutes 'hardly' mattered. Every town set its own clocks by the sun, so it did not keep London time, and Bristol is an example of a general pattern, not the only case. The passage says nothing about the accuracy of clocks or about coach timetables.

Question 25

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Standard

Show the passage · Railway time

For most of history, time was local. A town set its clocks by the sun, calling it noon when the sun stood highest in its own sky. Because the sun appears to cross the sky from east to west, noon arrives a little later at each step westward: in Britain, Bristol's noon falls about ten minutes after London's. As long as travel was slow, nobody minded. A coach journey from London to Bristol took most of a day, and a traveller whose watch was ten minutes out by the local clock on arrival hardly noticed.

The railways changed this. A timetable has to say when a train will leave each station, and a timetable that used a different time at every stop was an invitation to confusion and, on lines where trains in both directions shared a single track, to collisions. In 1840 the Great Western Railway began running all its trains on London time, and within a decade most British railway companies had followed. Station clocks showed 'railway time', even where the town hall clock nearby still showed local time.

For some years many towns lived with two times at once. Bristol's Corn Exchange clock was given a second minute hand so that it could show both. Some townspeople resented being told when noon was by a company in London, and a few councils held out for years. But the practical case was hard to resist: the post, the telegraph and the newspapers increasingly ran to the railway's clock, and a town that kept its own time made itself awkward to deal with. In 1880 Parliament made Greenwich Mean Time the legal time throughout Great Britain.

The change is usually told as a story of technology, and the railways certainly forced the question. Yet the railway did not decide the answer. A country could have chosen one national time, several zones or none at all, and countries chose differently: in the United States, far wider than Britain, the railway companies divided the country into several zones in 1883 rather than adopt a single time. What the railways created was a need for agreement; the form the agreement took was settled by people arguing over convenience, pride and who should be in charge.

A town lies some distance to the east of London. Following the reasoning in the first paragraph, before railway time the town's own noon would have come:

Show answer and explanation

Answer: D

The passage says noon 'arrives a little later at each step westward'. Read the other way, it arrives a little earlier at each step eastward, so a town east of London reaches noon before London does. 'A little after' reverses the direction. Since Bristol's noon is after London's, the eastern town's noon is well before Bristol's, not after it. Railway stations play no part before railway time.

Question 26

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Challenging

Show the passage · Railway time

For most of history, time was local. A town set its clocks by the sun, calling it noon when the sun stood highest in its own sky. Because the sun appears to cross the sky from east to west, noon arrives a little later at each step westward: in Britain, Bristol's noon falls about ten minutes after London's. As long as travel was slow, nobody minded. A coach journey from London to Bristol took most of a day, and a traveller whose watch was ten minutes out by the local clock on arrival hardly noticed.

The railways changed this. A timetable has to say when a train will leave each station, and a timetable that used a different time at every stop was an invitation to confusion and, on lines where trains in both directions shared a single track, to collisions. In 1840 the Great Western Railway began running all its trains on London time, and within a decade most British railway companies had followed. Station clocks showed 'railway time', even where the town hall clock nearby still showed local time.

For some years many towns lived with two times at once. Bristol's Corn Exchange clock was given a second minute hand so that it could show both. Some townspeople resented being told when noon was by a company in London, and a few councils held out for years. But the practical case was hard to resist: the post, the telegraph and the newspapers increasingly ran to the railway's clock, and a town that kept its own time made itself awkward to deal with. In 1880 Parliament made Greenwich Mean Time the legal time throughout Great Britain.

The change is usually told as a story of technology, and the railways certainly forced the question. Yet the railway did not decide the answer. A country could have chosen one national time, several zones or none at all, and countries chose differently: in the United States, far wider than Britain, the railway companies divided the country into several zones in 1883 rather than adopt a single time. What the railways created was a need for agreement; the form the agreement took was settled by people arguing over convenience, pride and who should be in charge.

The author writes that 'the railway did not decide the answer'. Which one of the following, if true, would most weaken this claim?

Show answer and explanation

Answer: A

The author's claim is that people, not the railways, settled the form of standard time. If the railway companies' choice prevailed everywhere regardless of what anyone else wanted, the railways did decide the answer, which undercuts the claim. Years of national debate and towns holding out both fit the claim that people argued the matter out. Fewer collisions show why an agreed time was needed, which the author already accepts, and the order in which telegraph offices and newspapers changed says nothing about who chose the form.

Question 27

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Standard

Seed banks are often pictured as a last resort, to be opened only after a global disaster. The Svalbard Global Seed Vault, cut into a mountainside on a Norwegian island in the Arctic, has done much to encourage that picture. In practice, the first withdrawal from the vault came in 2015, and its cause was local: a research centre based near Aleppo could no longer use its own collection because of the war in Syria. The seeds it had sent to Svalbard as a backup were returned and replanted in Lebanon and Morocco. The vault's real value, in other words, may lie less in surviving the end of the world than in insuring individual collections against ordinary misfortune.

Which one of the following best expresses the main conclusion of the text?

Show answer and explanation

Answer: C

The final sentence, introduced by 'in other words', draws the conclusion: the vault's value may lie in insuring individual collections against ordinary misfortune. The first option is the popular picture the text argues against. The text says the centre could no longer use its collection, not that the collection was destroyed, and it says nothing about Arctic seed banks being the safest or about who deposited seeds first.

Question 28

Logic, Problem Solving & Reading Comprehension · Reading Comprehension · Challenging

Last year the council of a mid-sized town painted cycle lanes along its two main roads. In the twelve months since, the number of cyclists injured on those roads has risen from 14 to 19. A councillor argues that the lanes have made cycling more dangerous and should be removed. But counts of cyclists taken at the same points last year and this year show that the number of cycling trips on the two roads has roughly doubled. If so, the risk of injury to a cyclist on any one trip has fallen, even though the total number of injuries has gone up.

Which one of the following, if true, would most weaken the writer's conclusion that the risk of injury on each trip has fallen?

Show answer and explanation

Answer: E

The conclusion rests on the trips having doubled. If this year's count was taken in ideal weather and last year's over a mixed month, the apparent doubling may reflect the conditions of the count rather than a real rise, and the per-trip risk may not have fallen. Where injured cyclists were riding bears on the councillor's blame of the lanes, not on the per-trip rate, and injuries on other roads do not change these figures. The 28 threshold (14 x 2) is true and supports the writer, and seriousness is a different matter from the risk of being injured at all.

Question 29

Logic, Problem Solving & Reading Comprehension · Numerical Reasoning · Standard

A pharmacy sells a pack of 30 tablets for €12.00 and a pack of 50 of the same tablets for €18.00. By what percentage is the price per tablet in the larger pack lower than in the smaller pack?

Show answer and explanation

Answer: B

Small pack: €12.00 / 30 = €0.40 a tablet. Large pack: €18.00 / 50 = €0.36 a tablet. The saving is €0.04 on €0.40, and 0.04 / 0.40 = 10%. 'About 11%' divides by the wrong base (0.04 / 0.36), 4% mistakes four cents for a percentage, and 50% compares the pack prices (€6 on €12) without allowing for the different numbers of tablets.

Question 30

Logic, Problem Solving & Reading Comprehension · Numerical Reasoning · Standard

The mean mark of the 20 students in a group is 62. When a 21st student's mark is added, the mean of all 21 marks is 63. What mark did the 21st student score?

Show answer and explanation

Answer: D

Total before: 20 x 62 = 1,240. Total after: 21 x 63 = 1,323. The new mark is 1,323 - 1,240 = 83. The new student has to cover their own 63 and also add 1 mark for each of the 20 earlier students: 63 + 20 = 83. Answers of 63 or 64 ignore the effect on the other twenty marks.

Question 31

Logic, Problem Solving & Reading Comprehension · Numerical Reasoning · Standard

An infusion is set to deliver 1.2 litres at a constant rate over 8 hours. After it has run for 2 hours 20 minutes, the rate is doubled and kept at that level. How long after the start is the full 1.2 litres delivered?

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Answer: C

Original rate: 1,200 ml / 480 min = 2.5 ml a minute. In the first 140 minutes, 140 x 2.5 = 350 ml is delivered, leaving 850 ml. At the doubled rate of 5 ml a minute, that takes 850 / 5 = 170 minutes, or 2 h 50 min. Total: 2 h 20 min + 2 h 50 min = 5 h 10 min. The other times come from applying the doubled rate to the wrong amount or the wrong stretch of time: only the 850 ml left after 140 minutes runs at 5 ml a minute.

Question 32

Logic, Problem Solving & Reading Comprehension · Numerical Reasoning · Standard

On a hospital ward the ratio of nurses to patients is 1 : 4. Ten more patients are then admitted and one more nurse comes on duty, and the ratio becomes 1 : 5. How many patients are now on the ward?

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Answer: E

Let there be n nurses and 4n patients at first. Afterwards 5(n + 1) = 4n + 10, so 5n + 5 = 4n + 10 and n = 5. There were 5 nurses and 20 patients; now there are 6 nurses and 30 patients, and 6 : 30 = 1 : 5. 20 is the number before the admissions, and 25 or 24 come from applying one of the ratios to the wrong number of nurses.

Question 33

Logic, Problem Solving & Reading Comprehension · Data Interpretation · Foundation

Which clinic had the largest percentage increase in the number of patients from 2024 to 2025?

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Answer: A

A: 240 / 1,200 = 20%. B: 225 / 900 = 25%. C fell by 80 / 1,600 = 5%. D: 210 / 750 = 28%. D has the largest percentage rise. A has the largest rise in numbers (240), which is the trap: a percentage rise is measured against each clinic's own starting figure.

Question 34

Logic, Problem Solving & Reading Comprehension · Data Interpretation · Standard

Show the passage · Four outpatient clinics

A regional health authority publishes yearly figures for its four outpatient clinics. For each clinic, the figures give the number of patients seen in 2024 and in 2025, the percentage of its 2025 patients who waited more than two weeks for a first appointment, and the number of doctors working there in 2025.

Clinic A: 1,200 patients in 2024; 1,440 in 2025; 15% of 2025 patients waited over two weeks; 6 doctors.

Clinic B: 900 patients in 2024; 1,125 in 2025; 20% of 2025 patients waited over two weeks; 5 doctors.

Clinic C: 1,600 patients in 2024; 1,520 in 2025; 20% of 2025 patients waited over two weeks; 8 doctors.

Clinic D: 750 patients in 2024; 960 in 2025; 30% of 2025 patients waited over two weeks; 3 doctors.

Which clinic had the largest number of patients who waited more than two weeks in 2025?

Show answer and explanation

Answer: C

A: 15% of 1,440 = 216. B: 20% of 1,125 = 225. C: 20% of 1,520 = 304. D: 30% of 960 = 288. C has the most, 304. D has the highest percentage, which tempts many to choose it, but it saw far fewer patients than C.

Question 35

Logic, Problem Solving & Reading Comprehension · Data Interpretation · Standard

Show the passage · Four outpatient clinics

A regional health authority publishes yearly figures for its four outpatient clinics. For each clinic, the figures give the number of patients seen in 2024 and in 2025, the percentage of its 2025 patients who waited more than two weeks for a first appointment, and the number of doctors working there in 2025.

Clinic A: 1,200 patients in 2024; 1,440 in 2025; 15% of 2025 patients waited over two weeks; 6 doctors.

Clinic B: 900 patients in 2024; 1,125 in 2025; 20% of 2025 patients waited over two weeks; 5 doctors.

Clinic C: 1,600 patients in 2024; 1,520 in 2025; 20% of 2025 patients waited over two weeks; 8 doctors.

Clinic D: 750 patients in 2024; 960 in 2025; 30% of 2025 patients waited over two weeks; 3 doctors.

Taking the four clinics together, by approximately what percentage did the total number of patients rise from 2024 to 2025?

Show answer and explanation

Answer: B

2024 total: 1,200 + 900 + 1,600 + 750 = 4,450. 2025 total: 1,440 + 1,125 + 1,520 + 960 = 5,045. The rise is 595, and 595 / 4,450 is about 0.134, or 13%. 17% is the simple average of the four clinics' own changes ((20 + 25 - 5 + 28) / 4), which wrongly gives a small clinic the same weight as a large one.

Question 36

Logic, Problem Solving & Reading Comprehension · Data Interpretation · Challenging

Show the passage · Four outpatient clinics

A regional health authority publishes yearly figures for its four outpatient clinics. For each clinic, the figures give the number of patients seen in 2024 and in 2025, the percentage of its 2025 patients who waited more than two weeks for a first appointment, and the number of doctors working there in 2025.

Clinic A: 1,200 patients in 2024; 1,440 in 2025; 15% of 2025 patients waited over two weeks; 6 doctors.

Clinic B: 900 patients in 2024; 1,125 in 2025; 20% of 2025 patients waited over two weeks; 5 doctors.

Clinic C: 1,600 patients in 2024; 1,520 in 2025; 20% of 2025 patients waited over two weeks; 8 doctors.

Clinic D: 750 patients in 2024; 960 in 2025; 30% of 2025 patients waited over two weeks; 3 doctors.

The authority's target is that no clinic should have more than 200 patients a year for each of its doctors. With 2025 patient numbers unchanged, and doctors unable to work at more than one clinic, what is the smallest total number of additional doctors needed for every clinic to meet the target?

Show answer and explanation

Answer: D

Each clinic needs at least its patients / 200 doctors, rounded up. A: 1,440 / 200 = 7.2, so 8 doctors, 2 more than 6. B: 1,125 / 200 = 5.625, so 6, 1 more. C: 1,520 / 200 = 7.6, so 8, which it already has. D: 960 / 200 = 4.8, so 5, 2 more. Total 2 + 1 + 0 + 2 = 5. Pooling the clinics (5,045 / 200 = 25.2, so 26 against 22 doctors) gives 4, as does rounding A's 7.2 down to 7, but doctors cannot be shared and 7 doctors would leave A above 200 each.

Question 37

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: The Chemistry of Living Things · Foundation

Which covalent bond, formed in a condensation reaction, links adjacent amino acids in the primary structure of a protein?

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Answer: B

The carboxyl group of one amino acid reacts with the amino group of the next, releasing a molecule of water and forming a peptide (amide) bond, -CO-NH-. Glycosidic bonds join monosaccharides, ester bonds join fatty acids to glycerol, and phosphodiester bonds join nucleotides. Hydrogen bonds hold the secondary structure together but are not covalent and do not form the chain itself.

Question 38

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: Cell Biology · Standard

Which of the following structures is found in both prokaryotic and eukaryotic cells?

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Answer: D

Every cell must make proteins, so prokaryotes and eukaryotes both have ribosomes (70S in prokaryotes, 80S in the eukaryotic cytoplasm). The nucleus, mitochondria, Golgi apparatus and endoplasmic reticulum are membrane-bound organelles, which prokaryotes lack: their DNA lies free in the cytoplasm in a region called the nucleoid.

Question 39

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: Cell Division and Genetics · Challenging

Red-green colour blindness is caused by a recessive allele carried on the X chromosome. A woman with normal vision, whose father was colour-blind, has children with a man with normal vision. What is the probability that their first child is a colour-blind boy?

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Answer: A

The woman received her father's only X, which carries the allele, so she is a carrier, X^B X^b; the man is X^B Y. The four equally likely children are X^B X^B, X^B X^b, X^B Y and X^b Y, and only X^b Y is a colour-blind boy, so the probability is 1/4. The tempting 1/2 is the probability that a son is colour-blind, which answers a different question: it is conditional on the child already being a boy.

Question 40

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: Metabolism and Bioenergetics · Standard

In a eukaryotic cell, where does the Krebs (citric acid) cycle take place?

Show answer and explanation

Answer: E

Pyruvate from glycolysis is carried into the mitochondrion, converted to acetyl-CoA in the link reaction, and oxidised in the Krebs cycle, all in the matrix. Glycolysis is the stage that happens in the cytoplasm. The inner membrane holds the electron transport chain and ATP synthase, and the intermembrane space is where protons accumulate during oxidative phosphorylation.

Question 41

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: Human Anatomy, Physiology and Homeostasis · Standard

When a person is dehydrated, antidiuretic hormone (ADH) is released and less water is lost in the urine. Of the parts of the kidney listed, where does ADH act to increase water reabsorption?

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Answer: C

ADH, released by the posterior pituitary, makes the cells of the collecting duct (and the late distal tubule) insert aquaporins into their membranes, so more water leaves the filtrate by osmosis into the concentrated medulla. The glomerulus and Bowman's capsule filter the blood rather than reabsorb from it. The proximal tubule and the descending limb do reabsorb water, but they do so whatever the ADH level.

Question 42

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Biology: Evolution, Ecology and Biotechnology · Foundation

In genetic engineering, what do restriction enzymes do?

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Answer: C

Restriction enzymes (restriction endonucleases) recognise a short, specific base sequence and cut both strands of the DNA there, often leaving sticky ends. Joining fragments is the job of DNA ligase, copying RNA into DNA is reverse transcriptase, unwinding the helix is helicase, and extending a strand in PCR is a heat-stable DNA polymerase.

Question 43

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: Matter and Atomic Structure · Foundation

An iron ion, Fe³⁺, has a mass number of 56. The atomic number of iron is 26. How many protons, neutrons and electrons does this ion contain?

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Answer: A

The atomic number gives 26 protons. Neutrons = mass number - atomic number = 56 - 26 = 30. A neutral atom has 26 electrons, and a 3+ charge means 3 have been lost, leaving 23. Adding electrons for a positive charge gives 29, taking 56 as the neutron count confuses it with the mass number, and the number of protons never changes when an ion forms.

Question 44

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: The Periodic Table and Chemical Bonding · Standard

Which of the following molecules contains polar bonds but is non-polar overall?

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Answer: E

Each C=O bond in CO₂ is polar, but the molecule is linear (O=C=O), so the two equal bond dipoles point in opposite directions and cancel. H₂O is bent and NH₃ is trigonal pyramidal, so their dipoles do not cancel. HCl has a single polar bond, and in CH₃Cl the C-Cl bond is not balanced by the three C-H bonds, so both are polar molecules.

Question 45

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: Stoichiometry and Solutions · Standard

What mass of sodium hydroxide, NaOH (molar mass 40 g/mol), is needed to make 250 mL of a 0.2 mol/L solution?

Show answer and explanation

Answer: B

Moles needed = concentration × volume = 0.2 mol/L × 0.250 L = 0.05 mol. Mass = 0.05 mol × 40 g/mol = 2.0 g. The answer 8.0 g is the mass for a whole litre (0.2 × 40), forgetting that only 250 mL is made; 0.5 g and 20 g are each out by a factor from mishandling the 250 mL to 0.250 L conversion or the molar mass.

Question 46

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: Acids, Bases and Redox · Challenging

In the reaction 2KMnO₄ + 16HCl → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O, which element is reduced, and how does its oxidation number change?

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Answer: D

In KMnO₄, K is +1 and four O are -8, so Mn is +7; in MnCl₂, with two Cl at -1, Mn is +2. Its oxidation number falls, so manganese is reduced, from +7 to +2. Chlorine does change, from -1 in HCl to 0 in Cl₂, but a rise is oxidation, so that is the species oxidised. Hydrogen and potassium stay at +1 throughout, and +6 is the oxidation number of Mn in the manganate ion, not in KMnO₄.

Question 47

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: Kinetics and Equilibrium · Standard

For the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g), the forward reaction is exothermic. Which change shifts the position of equilibrium so that more ammonia is present at equilibrium?

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Answer: C

There are 4 moles of gas on the left and 2 on the right, so by Le Chatelier's principle a higher pressure shifts the equilibrium towards the side with fewer gas moles, the ammonia side. Raising the temperature favours the endothermic, backward reaction, and lowering the pressure favours the side with more gas moles. Removing nitrogen shifts the equilibrium to the left. A catalyst speeds up both directions equally, so equilibrium is reached sooner but its position does not change.

Question 48

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Chemistry: Organic Chemistry · Standard

How many structural isomers have the molecular formula C₅H₁₂?

Show answer and explanation

Answer: A

The carbon skeleton can be a chain of five (pentane), a chain of four with a methyl branch on the second carbon (2-methylbutane), or a chain of three with two methyl groups on the middle carbon (2,2-dimethylpropane). Every other drawing is one of these three turned or renumbered: a methyl on carbon 3 of butane is still 2-methylbutane, and an ethyl branch on a four-carbon chain just makes a longer chain. Two is the answer for C₄H₁₀, not C₅H₁₂.

Question 49

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Numbers and Algebra · Foundation

What is the value of (2^5 × 4^3) / 8^3?

Show answer and explanation

Answer: D

Write every number as a power of 2: 4^3 = (2^2)^3 = 2^6 and 8^3 = (2^3)^3 = 2^9. The expression is 2^5 × 2^6 / 2^9 = 2^(5 + 6 - 9) = 2^2 = 4. Writing 8^3 as 2^6 instead of 2^9 gives 32, and similar slips with the indices give the other powers of 2 offered.

Question 50

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Equations and Inequalities · Standard

Which values of x satisfy the inequality x^2 - x - 6 ≤ 0?

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Answer: B

Factorise: x^2 - x - 6 = (x - 3)(x + 2), which is zero at x = 3 and x = -2. The parabola opens upwards, so it is at or below zero between its roots: -2 ≤ x ≤ 3. x ≤ -2 or x ≥ 3 describes where the expression is positive (or zero), -2 < x < 3 wrongly drops the endpoints where it equals zero, and the options with -3 and 2 come from a sign error in the factors.

Question 51

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Functions and Graphs · Standard

Given f(x) = 2x - 3 and g(x) = x^2 + 1, which expression is g(f(x))?

Show answer and explanation

Answer: E

Apply f first, then g: g(f(x)) = (2x - 3)^2 + 1 = 4x^2 - 12x + 9 + 1 = 4x^2 - 12x + 10. Check with x = 2: f(2) = 1 and g(1) = 2, and 16 - 24 + 10 = 2. The answer 2x^2 - 1 is f(g(x)), the other order; 4x^2 + 10 forgets the middle term of the square, and the cubic is the product f(x) × g(x).

Question 52

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Geometry and Trigonometry · Standard

What are the centre and the radius of the circle x^2 + y^2 - 6x + 8y = 0?

Show answer and explanation

Answer: C

Complete the square: (x - 3)^2 - 9 + (y + 4)^2 - 16 = 0, so (x - 3)^2 + (y + 4)^2 = 25. The centre is (3, -4) and the radius is sqrt(25) = 5. Taking the signs of the coefficients directly gives (-3, 4), 25 is the radius squared, and (6, -8) uses the coefficients without halving them.

Question 53

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Geometry and Trigonometry · Challenging

A triangle has sides of 5 cm, 7 cm and 8 cm. What is the size of the angle opposite the 7 cm side?

Show answer and explanation

Answer: A

By the cosine rule, cos θ = (5^2 + 8^2 - 7^2) / (2 × 5 × 8) = (25 + 64 - 49) / 80 = 40/80 = 1/2, so θ = 60°. It cannot be 90°, because 5^2 + 8^2 = 89 is not 49. A slip in the sign of 49 gives cos θ = -1/2 and 120°, which would also make 7 cm the longest side, and it is not.

Question 54

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Mathematics: Probability and Statistics · Standard

Two fair six-sided dice are thrown. What is the probability that the two scores add up to 8?

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Answer: D

There are 6 × 6 = 36 equally likely ordered outcomes. A total of 8 comes from (2, 6), (3, 5), (4, 4), (5, 3) and (6, 2): 5 outcomes, so the probability is 5/36. Counting (2, 6) and (6, 2) as one outcome would undercount, and 1/6 = 6/36 is the probability of a total of 7, the most likely sum.

Question 55

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Measurement and Kinematics · Foundation

A car starts from rest and accelerates uniformly at 2 m/s^2 for 5 s. How far does it travel in this time?

Show answer and explanation

Answer: E

From rest, s = (1/2)at^2 = (1/2) × 2 × 5^2 = 25 m. Equivalently, the final speed is 10 m/s, the average speed is 5 m/s, and 5 m/s × 5 s = 25 m. The answer 50 m uses the final speed as if it applied all the way, and 10 m is the final speed mistaken for a distance.

Question 56

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Measurement and Kinematics · Challenging

A stone is thrown vertically upwards at 20 m/s from the edge of a cliff 25 m above the sea. It rises, falls past the cliff edge and lands in the sea. Taking g = 10 m/s^2 and ignoring air resistance, how long after being thrown does it hit the water?

Show answer and explanation

Answer: B

Take upwards as positive with the origin at the cliff edge. The sea is at -25 m, so -25 = 20t - 5t^2, which gives t^2 - 4t - 5 = 0 and (t - 5)(t + 1) = 0. The physical root is t = 5 s. Check: after 5 s the displacement is 100 - 125 = -25 m. 2 s is the time to the top of the flight and 4 s the time to return to the cliff edge, before the extra 25 m fall.

Question 57

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Dynamics, Work and Energy · Standard

A 4 kg box on a horizontal floor is pulled by a horizontal force of 20 N. The friction force on the box is 8 N. What is the acceleration of the box?

Show answer and explanation

Answer: C

The resultant force is 20 N - 8 N = 12 N in the direction of the pull, and a = F/m = 12/4 = 3 m/s^2. Ignoring friction gives 20/4 = 5 m/s^2, adding the friction to the pull gives 28/4 = 7 m/s^2, and 8/4 = 2 m/s^2 uses the friction force alone.

Question 58

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Dynamics, Work and Energy · Challenging

A 2 kg block is released from rest at the top of a frictionless slope 5 m high. At the bottom it slides onto a rough horizontal surface where a constant friction force of 4 N acts on it. Taking g = 10 m/s^2, how far does the block slide along the rough surface before it stops?

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Answer: A

On the frictionless slope all the potential energy becomes kinetic energy: mgh = 2 × 10 × 5 = 100 J at the bottom. On the rough surface friction does work F × d to remove it, so 4 × d = 100 and d = 25 m. 50 m and 12.5 m come from doubling or halving that energy, for instance by mishandling the 1/2 in (1/2)mv^2, and 2.5 m divides mgh by the weight rather than the friction force; the slope's length does not matter, only its height.

Question 59

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Fluids and Thermodynamics · Foundation

Water has a density of 1000 kg/m^3. Taking g = 10 m/s^2, what is the pressure due to the water alone (not counting atmospheric pressure) at a depth of 5 m?

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Answer: D

Hydrostatic pressure is p = ρgh = 1000 × 10 × 5 = 50 000 Pa = 5 × 10^4 Pa. The answer 1.5 × 10^5 Pa adds atmospheric pressure (about 1 × 10^5 Pa), which the question excludes, and the other powers of ten come from slips in the arithmetic.

Question 60

Scientific Subjects (Biology, Chemistry, Mathematics & Physics) · Physics: Electricity and Magnetism · Challenging

A 2 Ω resistor is connected in series with a parallel pair of resistors, 6 Ω and 3 Ω, across a 12 V battery of negligible internal resistance. What is the current in the 3 Ω resistor?

Show answer and explanation

Answer: E

The parallel pair has resistance (6 × 3)/(6 + 3) = 2 Ω, so the total is 2 + 2 = 4 Ω and the battery current is 12/4 = 3 A. The parallel pair takes a potential difference of 3 A × 2 Ω = 6 V, so the current in the 3 Ω resistor is 6/3 = 2 A (and 1 A in the 6 Ω, which adds back to 3 A). 3 A is the total current, and 4 A comes from putting the full 12 V across the 3 Ω resistor.

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