GMAT Verbal: Strengthen/Weaken Arguments 2 — Questions and Answers
Question 1: A city claims that adding bike lanes reduced traffic accidents because accidents fell 20% the year after lanes were added. Which option most weakens this argument?
- The city also lowered the speed limit citywide that same year (Correct answer)
- Bike ridership increased after the lanes were added
- Neighboring cities without bike lanes saw no change
- The bike lanes were popular with residents
Correct answer: The city also lowered the speed limit citywide that same year
An alternative cause (the speed-limit drop) for the same drop in accidents undermines the claimed causal link.
Question 2: An ad argues that a supplement boosts memory because users scored higher on a memory test than non-users. Which assumption must be true for this to hold?
- Users and non-users were comparable in memory before taking it (Correct answer)
- The supplement is inexpensive
- The test was administered by a doctor
- Users took the supplement daily
Correct answer: Users and non-users were comparable in memory before taking it
The argument assumes the two groups were similar beforehand, so the difference reflects the supplement rather than pre-existing gaps.
Question 3: A manager argues that remote work lowers productivity because output dropped after the firm went remote. Which finding most strengthens the argument?
- Output per employee stayed low even after remote workers got better equipment (Correct answer)
- A competitor's output also dropped
- Employees reported preferring remote work
- The firm hired fewer new staff that year
Correct answer: Output per employee stayed low even after remote workers got better equipment
Ruling out a plausible alternative (poor equipment) and still seeing low output supports the claim that remote work itself is responsible.
Question 4: A study concludes coffee causes insomnia because heavy coffee drinkers report more sleeplessness. Which option most weakens this conclusion?
- People with insomnia drink more coffee to stay alert during the day (Correct answer)
- Coffee contains caffeine, a stimulant
- Light coffee drinkers also report some sleeplessness
- The study surveyed thousands of people
Correct answer: People with insomnia drink more coffee to stay alert during the day
It reverses the causation: insomnia may cause coffee consumption rather than the other way around.
Question 5: A politician argues a new tax cut will boost spending because past tax cuts were followed by higher consumer spending. Which most weakens the argument?
- The past cuts coincided with large stimulus checks that drove the spending (Correct answer)
- The tax cuts were unpopular with economists
- Spending is hard to measure precisely
- The new cut is smaller than the past ones
Correct answer: The past cuts coincided with large stimulus checks that drove the spending
Attributing the prior spending to stimulus checks removes the tax cut as the cause, undermining the prediction.
Question 6: An argument states that a school's new tutoring program raised test scores, citing higher scores after launch. Which most strengthens it?
- Only students who attended tutoring improved; non-attendees did not (Correct answer)
- The program was funded by a grant
- Teachers liked the new program
- Scores rose at a nearby school too
Correct answer: Only students who attended tutoring improved; non-attendees did not
A dose-response pattern—improvement only among participants—directly links the program to the higher scores.
Question 7: A company claims its rebranding caused a sales increase. Which question is most useful in evaluating this claim?
- Did sales rise for competitors who did not rebrand during the same period? (Correct answer)
- Was the new logo designed by an award-winning firm?
- Did employees approve of the rebrand?
- How much did the rebrand cost?
Correct answer: Did sales rise for competitors who did not rebrand during the same period?
Comparing to a control group that did not rebrand tests whether the rebrand, not a market-wide trend, drove sales.
GMAT Verbal: Strengthen/Weaken Arguments 2
A city claims that adding bike lanes reduced traffic accidents because accidents fell 20% the year after lanes were added.
Which option most weakens this argument?