Weekly Challenge
Five original questions for the week of August 10, 2026. No timer. Check each answer as you go.
A survey found that people who drink green tea daily are 40 percent less likely to catch a cold. The survey's authors conclude that drinking green tea boosts immunity.
Which of the following, if true, most seriously weakens the authors' conclusion?
An alternative cause does the damage. If tea drinkers also exercise and sleep more, those habits, not the tea, may explain the result.
No professional basketball player is under 5 feet 9 inches tall. Devon is 5 feet 8 inches tall.
Which of the following follows logically?
This is a direct contrapositive. If all pros are at least 5'9", then anyone shorter cannot be a pro. Nothing else is forced.
The library will close early on Fridays if foot traffic stays low. Foot traffic has stayed low every Friday this month.
The conclusion that the library will close early on Fridays follows logically if which of the following is assumed?
The premise is conditional on future traffic staying low, but the evidence is only about the past. Assuming the pattern holds bridges the gap completely.
Amara: "Rent control should be expanded citywide, because it is the fastest way to keep housing affordable for current residents." Ben: "Rent control might help current residents, but it reduces the incentive to build new housing, which makes the shortage worse over time."
The dialogue provides the most support for the claim that Amara and Ben disagree about whether
Amara backs expansion; Ben warns it backfires. They agree rent control can help current residents (C) but disagree on whether expanding it is a good idea overall.
Professor: "My course has a 98 percent pass rate, so it must be one of the easiest courses at the university."
The professor's reasoning is flawed because it
A high pass rate could mean easy material, or it could mean great teaching or strong students. The professor jumps to one explanation.
A free diagnostic shows your starting score, then a study plan tells you what to work on next.
Last updated October 12, 2026