Weekly Challenge
Five original questions for the week of September 21, 2026. No timer. Check each answer as you go.
A tutoring company advertises that its students improve their SAT scores by an average of 150 points, so its program must be effective.
Which of the following, if true, most weakens the advertised claim?
Survivorship bias. If only the improvers are counted, the average is inflated and says nothing about the program's real effect.
Some of the runners in the race are marathon veterans. All marathon veterans have completed at least one 26-mile race.
Which of the following follows logically?
Some runners are veterans, and all veterans have run 26 miles. So some runners in this race have run 26 miles. Nothing more follows.
The bridge is safe to cross. It was inspected last month and passed every test.
Which of the following, if assumed, makes the conclusion follow logically?
B states a universal rule that covers this bridge exactly, closing the gap between "passed last month" and "safe now."
Omar: "The city should fund the arts center because it will attract tourists and boost local business." Priya: "Tourism revenue is unpredictable, so the city should fund the arts center because residents deserve cultural spaces, not because of tourists."
Omar and Priya disagree about whether
Both agree the center should be funded (A is agreed). They disagree on the reason: Omar says tourism, Priya rejects that reason.
Drinking coffee must be healthy. My grandfather drank five cups a day and lived to 95.
The flaw in the reasoning is that it
One long-lived coffee drinker proves nothing about coffee in general. This is hasty generalization from a sample of one.
A free diagnostic shows your starting score, then a study plan tells you what to work on next.
Last updated October 12, 2026