Free practice questions/GMAT Focus Edition

GMAT Focus Edition — Critical Reasoning: Assumption & Strengthen/Weaken

6 free practice questions with full explanations.

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Question 1

A nutrition company claims that its new granola bar helps people lose weight because a survey found that 80% of customers who ate the bar daily for a month reported weight loss. Which of the following, if true, would most strengthen the company's claim?

A) The granola bar contains fewer calories than a typical candy bar.
B) The surveyed customers did not significantly change any other eating or exercise habits during the month.
C) The company has sold the granola bar for five years.
D) Some customers found the granola bar tasty.

Show answer & explanation

Correct answer: B) The surveyed customers did not significantly change any other eating or exercise habits during the month.

The claim is that the bar itself caused weight loss. If customers changed nothing else about their diet or exercise, it strengthens the case that the bar was the responsible factor, ruling out alternative explanations.

Question 2

A study found that employees who take short breaks every hour report higher job satisfaction than employees who take breaks less frequently. The study's authors conclude that mandating hourly breaks will increase job satisfaction company-wide. Which of the following, if true, would most weaken this conclusion?

A) Employees who already have engaging, low-stress jobs are more likely to take breaks voluntarily and also report higher satisfaction.
B) Some employees dislike being interrupted during focused work.
C) The study included employees from multiple industries.
D) Break rooms in the office are comfortable and well-stocked.

Show answer & explanation

Correct answer: A) Employees who already have engaging, low-stress jobs are more likely to take breaks voluntarily and also report higher satisfaction.

This suggests a third factor (job quality) causes both frequent breaks and higher satisfaction, meaning the correlation may not indicate that breaks themselves cause satisfaction. This undermines the conclusion that mandating breaks would replicate the effect.

Question 3

A publisher decides to stop printing physical copies of its magazine and move entirely to a digital format, reasoning that this will increase overall readership because digital content is more accessible. Which of the following is an assumption necessary for this argument?

A) Digital magazines are cheaper to produce than print magazines.
B) A significant portion of the potential readership has reliable access to digital devices and the internet.
C) Competing magazines have already gone digital.
D) The publisher's current readers prefer digital content.

Show answer & explanation

Correct answer: B) A significant portion of the potential readership has reliable access to digital devices and the internet.

The argument assumes accessibility will increase because of the digital switch. This only holds if the target audience actually has the means to access digital content; if many potential readers lack internet access, the switch could reduce readership instead.

Question 4

A city council proposes that installing streetlights along a poorly lit road will reduce nighttime accidents there. Which of the following, if true, would most strengthen this proposal?

A) The road is used by both pedestrians and cyclists.
B) On similar roads in the region, installing streetlights was followed by a significant drop in nighttime accidents.
C) Streetlight installation costs have decreased in recent years.
D) The road has more accidents than any other road in the city.

Show answer & explanation

Correct answer: B) On similar roads in the region, installing streetlights was followed by a significant drop in nighttime accidents.

Evidence of a similar intervention producing the desired effect elsewhere directly supports the claim that the same intervention would work on this road, strengthening the causal argument.

Question 5

A city plans to reduce traffic congestion by adding a new express bus lane on its busiest highway. City planners argue this will encourage more commuters to use buses instead of driving, thereby reducing the number of cars on the road. Which of the following is an assumption underlying the planners' argument?

A) The express bus lane will not be used by carpooling vehicles.
B) A meaningful number of current drivers would be willing to switch to buses if commute times improved.
C) The city has enough buses to run an express service.
D) Traffic congestion is worse during morning commutes than evening commutes.

Show answer & explanation

Correct answer: B) A meaningful number of current drivers would be willing to switch to buses if commute times improved.

The argument concludes that adding the lane will reduce car traffic because more people will switch to buses. This requires assuming that drivers are actually willing to make that switch given a faster bus option; if no one would switch regardless of speed, the plan would fail.

Question 6

A company notices that employees who complete a leadership training program are promoted at twice the rate of those who do not. The company concludes that the training program causes employees to become better leaders and thus more promotable. Which of the following, if true, would most weaken this conclusion?

A) The training program is only two days long.
B) Employees are not required to take the training program.
C) Managers tend to select their most promising employees to attend the training program in the first place.
D) The training program covers topics like communication and delegation.

Show answer & explanation

Correct answer: C) Managers tend to select their most promising employees to attend the training program in the first place.

If employees are selected for training because they are already seen as promising, the higher promotion rate could be due to pre-existing potential rather than the training itself, weakening the causal claim.

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