LSAT Logical Reasoning: Weaken the Argument Questions

Question 1

A city council member argues that building a new highway through the suburbs will reduce downtown traffic congestion because commuters will have a faster route into the city. Which of the following, if true, most weakens this argument?

Accepted Answer

Studies show that new roads attract additional drivers, increasing total traffic volume.

Answer

The argument assumes the highway will reduce congestion, but if new roads attract additional drivers (induced demand), total traffic volume could increase rather than decrease.

Question 2

A nutritionist claims that people who eat breakfast daily perform better at work than those who skip breakfast, citing a study of office workers. Which of the following most weakens this argument?

Accepted Answer

People who eat breakfast may also engage in other healthy habits that improve performance.

Answer

This introduces a confounding variable: breakfast eaters may have other healthy habits (better sleep, exercise) that actually cause better performance, making breakfast merely correlative, not causal.

Question 3

An economist argues that raising the minimum wage will increase unemployment because businesses will hire fewer workers when labor costs rise. Which of the following, if true, most weakens this conclusion?

Accepted Answer

Higher wages increase consumer spending, which can create additional jobs.

Answer

If higher wages increase consumer spending sufficiently to create new jobs, the net employment effect could be neutral or positive, directly undermining the unemployment prediction.

Question 4

A school principal argues that eliminating recess will improve student academic performance because students will have more time for instruction. Which of the following most weakens this argument?

Accepted Answer

Research shows that physical activity improves concentration and cognitive function.

Answer

If physical activity during recess improves students' ability to concentrate and learn, removing recess could decrease learning efficiency enough to offset any gains from additional instruction time.

Question 5

A pharmaceutical company argues that its new drug is safe because none of the 200 participants in its clinical trial experienced serious side effects. Which of the following most weakens this argument?

Accepted Answer

Some serious side effects may only manifest after long-term use exceeding the trial duration.

Answer

If serious side effects only emerge after long-term use, a short-term trial cannot establish long-term safety, directly undermining the safety claim.

LSAT - Law School Admission Test Practice Test

LSAT - Law School Admission Test Practice Test

LSAT Logical Reasoning: Weaken the Argument Questions