Having an issue with the following problem that I found in a review book:
No one reads "Weight-Off" magazine unless he or she is fat. Everyone reads "Weight-Off" magazine unless he or she eats chocolate.
Which of the following is inconsistent with the above?
A. No one is fat and only some people eat chocolate
B. Some people are fat and no one eats chocolate
C. Everyone is fat
D. No one is fat and no one reads "Weight-Off"
E. No one who is fat eats chocolate
The official answer is A.
But why is it not B? If no one eats chocolate, then that implies that "everyone" reads the magazine. But if only SOME people are fat, how can "everyone," including non-fat people read it (since that goes against the first premise)?
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cynthiad wrote:It doesn't say that *only* some people are fat. So if everyone is fat, then it's also true that some people are fat.
QFT - for answer 'B', it helps to mentally add "at least" to the beginning of the answer to remind you that "some" is a subset of "everyone".
Answer 'A' is a flat-out impossible situation, though. If only some people eat chocolate (see how they slipped the 'only' in there, so you can't claim that everyone eats chocolate?), then those who don't eat chocolate must read the magazine, which means that they're fat. Since there are at least some fat people, answer 'A' is inconsistent with the conditions given.