All board members support the new policy. The board has final authority over policy changes. Therefore, the new policy will be adopted. Which statement is the conclusion?
The other statements support the claim that the policy will be adopted, so that claim is the conclusion.
ข้อ 2
Cars in this city produce most of the air pollution. Expanding the subway would reduce car use. If car use falls, pollution will drop. So expanding the subway would improve air quality. Which statement is the conclusion?
The conclusion is the final claim that the premises are offered to support.
ข้อ 3
Studies show students who sleep at least eight hours score higher. Sleep improves memory consolidation. Therefore, students should prioritize enough sleep before exams. Which statement is the conclusion?
The recommendation is the conclusion; the other statements provide evidence for it.
ข้อ 4
The new software costs more to install. However, it reduces server downtime and lowers maintenance costs. Thus, the software will save money over time. Which statement is the conclusion?
The cost and maintenance facts support the final prediction that the software saves money.
ข้อ 5
Company profits have risen for three years. The company expanded into online sales during that period. Online sales are likely the main cause of growth. Which statement is the conclusion?
The profit and expansion facts are used to support the claim about online sales causing growth.
ข้อ 6
Regular exercise reduces stress and improves heart health. People who exercise also report better sleep. Therefore, regular exercise benefits overall health. Which statement is the conclusion?
The listed benefits support the general conclusion that exercise benefits overall health.
ข้อ 7
The city will reduce traffic by building more bike lanes. The plan assumes that ___.
For bike lanes to reduce traffic, enough car users must actually switch to bicycles.
ข้อ 8
This medicine is safe because it passed all required trials. The argument assumes that ___.
The argument depends on the assumption that passing the required trials guarantees safety.
ข้อ 9
The survey shows most students prefer online classes, so the school should offer more. The argument assumes that ___.
The conclusion depends on the sample representing the larger student population.
ข้อ 10
The restaurant is popular, so its food must be excellent. The argument assumes that ___.
The argument links popularity directly to quality, so that link is the unstated assumption.
ข้อ 11
Since the machine was repaired yesterday and worked today, the repair fixed it. The argument assumes that ___.
The conclusion depends on the repair being the only relevant change between yesterday and today.
ข้อ 12
The new training improved employee productivity. The argument assumes that ___.
For the comparison to be valid, productivity must be measured under fair and comparable conditions.
ข้อ 13
A study suggests eating breakfast improves concentration. Which choice would most strengthen the argument?
Independent replication with a larger sample makes the causal claim much more credible.
ข้อ 14
Bike lanes reduce accidents. Which choice would most strengthen the argument?
Observed accident reductions in cities with bike lanes directly supports the claim.
ข้อ 15
The new tax will reduce smoking. Which choice would most strengthen the argument?
Evidence from comparable situations supports the prediction that higher prices reduce smoking.
ข้อ 16
Remote work increases productivity. Which choice would most strengthen the argument?
A real-world case showing higher output after switching to remote work supports the claim.
ข้อ 17
Smaller class sizes improve learning. Which choice would most strengthen the argument?
The test-score evidence connects smaller classes to improved learning outcomes.
ข้อ 18
Reading fiction improves empathy. Which choice would most strengthen the argument?
The empathy-score comparison directly supports the claimed effect of reading fiction.
ข้อ 19
Because our city added bike lanes, accidents fell. Therefore, bike lanes reduce accidents. Which choice would most weaken the argument?
The speed-limit change is an alternative cause that could explain the accident decrease.
ข้อ 20
The company's profits rose after the new CEO arrived. Therefore, the CEO caused the growth. Which choice would most weaken the argument?
A broad economic recovery provides an alternative explanation for rising profits.
ข้อ 21
Students who attended the prep course scored higher. Therefore, the course works. Which choice would most weaken the argument?
If stronger students selected the course, the score difference may reflect selection rather than the course.
ข้อ 22
People who drink green tea live longer. Therefore, green tea extends life. Which choice would most weaken the argument?
Healthy habits are an alternative cause of the longer lifespans, weakening the tea claim.
ข้อ 23
The town banned plastic bags and litter decreased. Therefore, the ban caused the decrease. Which choice would most weaken the argument?
The simultaneous recycling program is an alternative explanation for the litter decrease.
ข้อ 24
Higher salaries attract better employees. The company raised salaries and quality improved. Therefore, the raise caused the improvement. Which choice would most weaken the argument?
The new hiring process is an alternative cause of the quality improvement.
ข้อ 25
All managers in this company have degrees. Maria has a degree. Therefore, Maria is a manager. Which flaw does the argument commit?
A degree is necessary for being a manager here, but it is not sufficient; other people can have degrees too.
ข้อ 26
The last three applicants were friendly, so the next applicant will also be friendly. Which flaw does the argument commit?
Three examples are far too few to support a prediction about the next applicant.
ข้อ 27
The newspaper made one factual error, so its other claims must be false. Which flaw does the argument commit?
One mistake does not prove that unrelated claims are false.
ข้อ 28
Either we cut taxes or the economy will fail. We cannot cut taxes, so the economy will fail. Which flaw does the argument commit?
The argument presents only two options when other policies may also improve the economy.
ข้อ 29
My neighbor drives fast and has never had an accident, so speed limits are unnecessary. Which flaw does the argument commit?
One personal example is anecdotal and cannot support a general policy conclusion.
ข้อ 30
People who wear glasses are intelligent. Most professors wear glasses. Therefore, wearing glasses makes people intelligent. Which flaw does the argument commit?
The argument assumes that the correlation between glasses and intelligence is a causal relationship.
ข้อ 31
All employees at this company must pass a background check. Some employees work remotely. Which statement is most strongly supported?
Because some employees work remotely and all employees must pass the check, at least one remote employee has passed it. The other choices add claims the premises do not support.
ข้อ 32
Every successful applicant in the program has strong writing skills. Maria is an applicant and has strong writing skills. Which conclusion is most strongly supported?
Strong writing is necessary for acceptance, but the premises do not show that it is sufficient, so Maria may still be rejected.
ข้อ 33
If a city has more parks, its residents exercise more. City A has more parks than City B. Which statement is best supported?
The conditional supports the comparison that City A residents exercise more, assuming other conditions are similar; it does not support the stronger claims.
ข้อ 34
The shipment arrived late because the port was closed during a storm. The port has reopened. Which statement is most strongly supported?
If the storm closure caused the delay, the delay does not reflect the company's ordinary reliability.
ข้อ 35
Political scientists note that countries with independent courts attract more foreign investment. The writer concludes that strengthening judicial independence will boost investment. Which role does the first sentence play?
The correlation between independent courts and investment is used as evidence to support the recommendation.
ข้อ 36
Proponents argue that electric buses reduce emissions. Critics reply that their cost is high and charging infrastructure is limited. Which role does the claim about charging infrastructure play?
The critic uses limited charging infrastructure as a reason against the proposal.
ข้อ 37
Some doctors say the new drug is effective because two studies found fewer symptoms. Critics respond that both studies were small and industry-funded. How is the critics' response used?
The critics attack the quality of the evidence rather than directly asserting the drug is ineffective.
ข้อ 38
Principle: A store should honor a posted price only when a reasonable customer would have understood the price as final. Situation: A store's website listed a laptop for $199 instead of $1,999, and the error was corrected within an hour. Which application is most consistent with the principle?
The dramatic error and quick correction make it unreasonable to treat $199 as a final posted price, so the principle does not require honoring it.
ข้อ 39
Principle: Schools should provide accommodations when a student's disability substantially limits access to instruction. Situation: A student with a documented condition cannot use the standard online exam format. Which application is most consistent?
An accessible format directly addresses the limitation while preserving the exam requirement.
ข้อ 40
A bookstore raised its prices and expected fewer customers, yet its revenue increased. Which would best resolve the paradox?
If customers bought more books, total revenue can rise even when the number of customers falls.
ข้อ 41
City X added recycling bins to every park, yet the amount of waste sent to its landfill increased. Which would best resolve the paradox?
The measured increase may reflect a broader reporting area rather than less recycling by residents.
ข้อ 42
To graduate, students at the college must complete an internship. Which statement follows?
The internship is a necessary condition: graduation implies it, but completing it does not guarantee graduation.
ข้อ 43
A researcher wants to determine whether a new fertilizer increases crop yield. Which design most directly tests the claim?
Random assignment and a control group isolate the fertilizer's effect from other factors.
ข้อ 44
Politician: My opponent promises lower taxes, but she also supports new spending. These positions cannot both work. Which method of argument is used?
The politician attacks the coherence of the two positions rather than the opponent personally.
ข้อ 45
If it rains, the ground is wet. The ground is wet, so it rained. Which argument is most similar in reasoning?
The original affirms the consequent; the matching argument does the same, treating a necessary condition as sufficient.
ข้อ 46
A study found that people who take vitamin D have fewer colds. Which finding would most strengthen the conclusion that vitamin D prevents colds?
Randomized evidence directly supports the causal claim and controls for alternative explanations present in observational data.
ข้อ 47
A city claims that its new bike-sharing program reduced traffic because traffic fell after launch. Which choice would most weaken the argument?
Expanded bus service and tolls are alternative causes that could explain the traffic decline.
ข้อ 48
Principle: A school should refund a course fee only if the student withdrew before the course began. Situation: A student withdrew three days after the course started. Which application is most consistent?
The principle makes withdrawal before the course began necessary for a refund, and the student did not meet that condition.
ข้อ 49
Which of the following would weaken the argument that banning sugar-sweetened drinks reduces obesity? Select all that apply.
Substitution and a similar decline without the ban both provide alternative explanations for the observed change.
ข้อ 50
A university claims its online program is as effective as its in-person program because final exam scores were equal. Which assumptions must hold for the comparison? Select all that apply.
Comparable exams and comparable starting ability are needed for equal scores to support equal effectiveness; completion rate and instructor preference are not necessary to that claim.
ข้อ 51
Which of the following are common flaws when an argument moves from correlation to causation? Select all that apply.
A third variable and reversed causation are classic alternatives that undermine causal conclusions; controlling confounds and random assignment strengthen studies.
ข้อ 52
A doctor wants to test whether a new therapy reduces anxiety. Which elements make the study more persuasive? Select all that apply.
Random assignment and a placebo control reduce bias; self-selection and a small sample weaken the evidence.
ข้อ 53
Which statements about necessary and sufficient conditions are correct? Select all that apply.
Necessity means B requires A; sufficiency means A is enough for B. The other choices reverse those meanings.
ข้อ 54
Which of the following would strengthen the argument that remote work improves mental health? Select all that apply.
Longitudinal evidence and reported balance directly support the claim; cost savings are irrelevant, and existing flexibility is a possible alternative explanation.
ข้อ 55
Which of the following are legitimate ways to evaluate the strength of an argument? Select all that apply.
Premise support, hidden assumptions, and competing explanations are central to evaluation; popularity does not determine logical strength.
ข้อ 56
An argument can be logically valid even if one of its premises is false.
Validity concerns the relationship between premises and conclusion; a valid argument can still have false premises.
ข้อ 57
If a study finds a correlation between two variables, it proves that one causes the other.
Correlation alone does not establish causation; other explanations and study design must be considered.
ข้อ 58
An assumption is a claim that an argument must accept for its reasoning to work.
Assumptions are unstated claims the argument relies on; identifying them is a core LSAT skill.
ข้อ 59
A single counterexample can be enough to refute a universal claim.
A universal claim asserts that something holds in every case, so one genuine counterexample falsifies it.
ข้อ 60
Complete the term: An argument that attacks the person instead of the argument commits the ___ fallacy.
Ad hominem means against the person; it attacks the speaker rather than addressing the reasoning.