Practice Logical Reasoning questions for the Law School Admission Test. Every question includes a full explanation of why the correct answer is right and why the tempting distractors are wrong.
10 example questions with full explanations. Use the interactive practice above to work through the complete set.
Question 1hard
A pharmaceutical company argues: 'Our new drug reduces average recovery time from illness X by 30%. In our clinical trial, patients who took the drug recovered in an average of 7 days, compared to 10 days for the control group. Therefore, doctors should prescribe this drug to all patients diagnosed with illness X.' Select all that apply: Which of the following, if true, would most seriously weaken this argument?
- A.The clinical trial excluded patients over age 65, who constitute 40% of all illness X diagnoses and who metabolize the drug differently than younger patients.✓
- B.A competing drug approved five years ago reduces recovery time from illness X by an average of 35% with fewer reported side effects than the new drug.✓
- C.Some physicians who participated in the clinical trial also hold consulting contracts with the pharmaceutical company that funded the study.✓
- D.The drug costs less per dose than the average cost of one additional day of illness-related lost productivity.
Correct answer: A, B, C
A weakens the argument by revealing the clinical trial excluded a major demographic (40% of patients), meaning the conclusion that 'all patients' should receive the drug is unsupported — the data does not apply to elderly patients. B weakens the argument by introducing a superior alternative, undermining the prescriptive conclusion that doctors should choose this drug. C weakens the argument by raising a conflict of interest that casts doubt on the reliability of the trial's results. D actually strengthens or is neutral to the argument — it provides economic justification for prescribing the drug, which does not weaken the conclusion. The argument's conclusion is about prescribing the drug universally, and A, B, and C each attack different premises supporting that conclusion from different angles (scope, comparative efficacy, and methodological integrity).
Question 2hard
A city council member argues: 'We must either build a new highway or expand public transit to solve our congestion problem. Expanding public transit is too expensive given our current budget deficit. Therefore, we must build a new highway. And since building a new highway will attract new commercial development along the corridor, our tax revenue will increase, which will eventually eliminate the budget deficit.' Select all that apply: Which of the following identify a flaw in the council member's reasoning?
- A.The argument presents only two solutions to the congestion problem while ignoring other possible approaches, such as congestion pricing or remote work incentives.✓
- B.The argument uses the budget deficit to rule out one option, then relies on the chosen option to eliminate the very deficit used as a justification.✓
- C.The argument assumes that commercial development will necessarily follow highway construction without establishing that this causal relationship will hold in this specific case.✓
- D.The argument fails to consider that building a new highway may itself be expensive, potentially worsening the budget deficit before any revenue benefits materialize.✓
Correct answer: A, B, C, D
All four options identify genuine flaws. A identifies a false dilemma — the argument assumes only two solutions exist when others (congestion pricing, zoning changes, remote work policies) may be viable. B identifies a circular or self-undermining justification: the budget deficit is used to eliminate the transit option, yet the conclusion depends on the highway eventually fixing that deficit, creating an internal inconsistency in the reasoning. C identifies an unwarranted causal assumption — commercial development 'will' follow is stated as certain when it is merely assumed; highway-adjacent development does not automatically occur. D identifies a neglected practical consideration that directly undermines the argument's internal logic: if highway construction itself worsens the deficit, the premise about affordability cuts against the chosen solution too. This is a hard question because test-takers must evaluate each option independently against multiple layers of the argument's structure.
Question 3medium
A pharmaceutical company recently announced that its new cholesterol drug reduces the risk of heart attack by 50 percent. Medical researchers noted, however, that the drug was tested exclusively on patients who already had heart disease and were taking multiple other medications. The researchers concluded that the announced benefit cannot be reliably extended to the general population.
The researchers' conclusion is most strongly supported if which of the following is assumed?
- A.Patients with pre-existing heart disease respond to medications differently than healthy individuals do.✓
- B.The pharmaceutical company deliberately excluded healthy individuals from its trial to manufacture favorable results.
- C.No cholesterol drug has ever demonstrated a 50 percent reduction in heart attack risk in the general population.
- D.Heart disease is primarily caused by factors unrelated to cholesterol levels.
Correct answer: A
The researchers argue that results from a specific subgroup (heart disease patients on multiple medications) cannot be generalized to the broader population. For this conclusion to hold, there must be a meaningful difference between the test group and the general population — specifically, that the two groups respond differently to the drug. Answer A supplies exactly this assumption: if heart disease patients respond differently than healthy individuals, the trial results do not transfer to the general population. Answer B introduces intent, which is irrelevant to whether the results are generalizable. Answer C addresses historical precedent rather than the validity of extending this study's findings. Answer D concerns the causes of heart disease, which does not bear on whether the drug's measured effect in one group applies to another.
Question 4medium
Editorial: The city council argues that installing surveillance cameras throughout the downtown area will deter crime and make residents safer. Yet cities that have installed such cameras have not seen significant reductions in violent crime rates. Moreover, the cameras are expensive to maintain and have repeatedly been shown to displace crime to adjacent neighborhoods rather than eliminate it. Therefore, the city council's proposal will not achieve its stated goal of making residents safer.
The main conclusion of the editorial is best expressed as which of the following?
- A.Surveillance cameras are too expensive for the city to install and maintain responsibly.
- B.The city council's surveillance camera proposal will fail to accomplish what the council says it is intended to accomplish.✓
- C.Cameras displace crime to neighboring areas rather than reducing the overall level of crime.
- D.Cities that have installed surveillance cameras have not experienced significant drops in violent crime.
Correct answer: B
The editorial's main conclusion is the final claim the argument is building toward: that the proposal will not achieve its stated goal of making residents safer. Answer B captures this precisely, tying the council's own stated purpose to the predicted failure. Answers C and D are premises used to support the main conclusion — they are evidence, not the point the argument is trying to establish. Answer A mentions cost, which is cited as a secondary concern but is not the editorial's central claim; the argument's thrust is about effectiveness, not budget.
Question 5medium
If a country's central bank raises interest rates, borrowing costs for businesses increase. When borrowing costs increase, businesses reduce capital investment. When businesses reduce capital investment, economic growth slows. Trentovia's central bank raised interest rates last quarter.
Which of the following must be true on the basis of the statements above?
- A.Trentovia's economy is currently in a recession.
- B.Trentovia's central bank will continue raising interest rates in future quarters.
- C.Trentovia's businesses have reduced their capital investment.✓
- D.Trentovia's economic growth rate is now lower than that of any country that did not raise interest rates.
Correct answer: C
The statements form a conditional chain: raising interest rates → increased borrowing costs → reduced capital investment → slowed growth. Since Trentovia's central bank raised interest rates, we can follow the chain: borrowing costs increased, and therefore businesses reduced capital investment. Answer B correctly captures the second step in this chain and must be true. Answer A goes too far — slowed growth is not the same as a recession, and we cannot infer a recession from the premises. Answer B makes a prediction about future policy not supported by the statements. Answer D introduces a comparison to other countries, which the argument provides no basis for.
Question 6medium
Historian: During the Renaissance, European painters began depicting human figures with unprecedented anatomical accuracy, a development often attributed to increased study of human cadavers. However, the most anatomically precise paintings of the era were produced by artists who had no documented access to cadavers. Therefore, cadaver study cannot fully explain the surge in anatomical accuracy during this period.
The historian's argument proceeds by
- A.drawing an analogy between artistic development and scientific methodology to challenge a historical consensus.
- B.demonstrating that the conventional explanation is entirely false by identifying an exception.
- C.conceding that cadaver study influenced some painters while arguing it had no effect on the Renaissance as a whole.
- D.providing a counterexample that undermines the sufficiency of an accepted explanation.✓
Correct answer: D
The historian acknowledges the conventional explanation (cadaver study) and then introduces a counterexample — artists without cadaver access produced the most accurate work — to show that cadaver study alone cannot fully account for the phenomenon. This is precisely what answer C describes: using a counterexample to undermine the sufficiency of the accepted explanation. Answer A is wrong because no analogy to scientific methodology is drawn. Answer B overstates the argument; the historian says cadaver study 'cannot fully explain' the trend, not that the explanation is entirely false. Answer C misrepresents the argument — the historian does not concede a partial effect of cadaver study, nor does the argument address the Renaissance as a whole versus some painters.
Question 7medium
A city council recently doubled the fines for illegal parking in the downtown district. The council argued this would significantly reduce parking violations. However, a transportation analyst noted that in comparable cities where similar fine increases were implemented, the number of parking violations actually decreased by only 3% on average — a negligible change. The analyst concluded that doubling the fines would be similarly ineffective in this city.
Which of the following, if true, most strengthens the analyst's conclusion?
- A.Surveys of downtown drivers in this city show that most violators are aware of and indifferent to the current fine amounts when deciding where to park.✓
- B.The downtown district has fewer available parking spaces than comparable cities that doubled their fines.
- C.The city council did not consult transportation experts before deciding to double the fines.
- D.Some comparable cities that doubled their fines subsequently invested the additional revenue in expanded public transportation.
Correct answer: A
The analyst's conclusion is that doubling fines will be ineffective at reducing violations in this city. Choice A strengthens this by showing that this city's drivers are already indifferent to fine amounts — meaning financial deterrence does not drive their behavior, making a fine increase unlikely to change outcomes. Choice A actually weakens the conclusion by introducing a structural reason (parking scarcity) that could independently explain violations, suggesting the comparison to other cities is flawed. Choice C attacks the council's process but says nothing about whether the policy will work. Choice D describes what some comparable cities did with revenue, which is irrelevant to whether the fine increase reduced violations in this city.
Question 8medium
Historian: During the fifteenth century, the city of Bruges was one of the wealthiest trading centers in Europe. Yet within a century, its commercial prominence had almost entirely collapsed. Many scholars attribute this decline to the silting of the Zwin estuary, which cut off Bruges from sea access. However, records show that merchants began relocating to Antwerp nearly two decades before the Zwin became impassable. Therefore, the silting of the Zwin cannot be the primary explanation for Bruges's commercial decline.
The historian's argument proceeds by:
- A.Presenting a counterexample that disproves the scholarly consensus about Bruges.
- B.Citing evidence that the proposed cause occurred after the effect it is supposed to have produced.✓
- C.Arguing that because two events are correlated, one must have caused the other.
- D.Offering an alternative explanation for Bruges's decline to replace the one being rejected.
Correct answer: B
The historian argues that the Zwin silting cannot be the primary cause of Bruges's decline because merchants left for Antwerp before the silting became impassable — meaning the proposed cause (silting) occurred after the effect (merchant departure) it was supposed to explain. This is a classic method of undermining a causal claim by showing the temporal order is wrong. Choice A is incorrect because the historian does not offer a counterexample that disproves the consensus outright — a single chronological observation is not a counterexample in that sense. Choice C describes the opposite error (affirming causation from correlation), which the historian is not committing. Choice D is incorrect because the historian does not offer any alternative explanation for the decline — only rejects the existing one.
Question 9medium
A country implements a new policy requiring all students to complete two years of a foreign language in secondary school. Supporters claim this will produce a generation of bilingual citizens. Critics respond that studies consistently show students who learn a foreign language only in classroom settings, without immersive exposure, rarely achieve functional fluency. Therefore, the policy will not produce a bilingual generation.
Which of the following arguments is most parallel in its logical structure to the critics' argument above?
- A.A gym chain advertises that its new high-intensity program will make members physically fit. However, research shows that high-intensity exercise without adequate rest leads to injury in most participants. Therefore, the program will not make members fit.
- B.A company claims its new training seminar will make all employees expert negotiators. However, most employees lack the natural aptitude for negotiation. Therefore, the seminar cannot be expected to produce expert negotiators.
- C.A city plans to reduce traffic by building more highways. However, studies show that adding highway capacity typically increases total vehicle traffic over time. Therefore, the plan will not reduce traffic.✓
- D.A school district argues that adding art classes will make students more creative. However, creativity depends on innate talent rather than instruction. Therefore, art classes will have no effect on student creativity.
Correct answer: C
The critics' argument structure is: (1) a policy is proposed to achieve a specific outcome; (2) evidence from studies shows that the method used by the policy generally fails to produce that outcome; (3) therefore, the policy will not achieve its goal. The key features are that the evidence against the policy comes from empirical studies about the method's general ineffectiveness — not from claims about inherent limitations of participants. Choice C matches this exactly: a city proposes highway expansion to reduce traffic, studies show that method typically increases traffic, so the plan will fail. Choice A introduces injury as an intermediate harm rather than showing the method fails to produce the intended outcome. Choice B relies on inherent aptitude limitations of participants, not empirical studies of the method. Choice C similarly appeals to innate talent, not study-based evidence about instructional methods.
Question 10medium
Last winter, the town of Kellford experienced both record low temperatures and a 40% spike in home heating system failures. The local utility company proposed that the record cold caused the surge in failures by overworking aging heating units. A consumer advocate, however, pointed out that many of the failed systems were less than five years old and had passed recent safety inspections. The advocate added that a nationwide recall of a heating component made by one manufacturer was issued just before the failures began.
If the statements above are all true, which of the following is most strongly supported?
- A.The record low temperatures had no role whatsoever in the increase in heating system failures in Kellford.
- B.The recalled heating component was the sole cause of the spike in heating system failures in Kellford.
- C.Safety inspections of heating systems are generally unreliable indicators of a system's performance under extreme conditions.
- D.The utility company's explanation does not fully account for all the heating system failures that occurred.✓
Correct answer: D
The utility company's explanation — that record cold overworked aging units — is undermined by the fact that many failed systems were less than five years old (not aging) and had recently passed safety inspections. This means the utility's explanation cannot fully account for all the failures. Choice C captures this precisely: the explanation is incomplete. Choice A goes too far by claiming temperatures had no role at all — the passage does not eliminate temperature as a contributing factor, only shows it cannot be the complete explanation. Choice B is also an overreach; the recall is offered as an alternative factor but the passage does not establish it as the sole cause. Choice C is an inference that stretches beyond what the passage supports — the inspections may have been accurate at the time and simply could not predict a manufacturing defect.