Official Solution:

Out of 100 people surveyed, 60 were women. If 10 were smoking women and 20 were smoking men, what percentage of men surveyed were non-smokers?

A. 10
B. 20
C. 30
D. 40
E. 50

There were \(100 - 60 = 40\) men surveyed. We further read that 20 men were smokers. Thus \(40-20=20\) men were non-smokers. We have enough information to answer the question. \(\frac{40 - 20}{40} = 50%\) of men surveyed were non-smokers. Note that the question stem gives us some redundant information about how many women were smokers.

Answer: E
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it's always wise to carefully read what the question is asking for, if it had been my first time answering this question then i too would have have answered 20%

I would avoid questions that assume that men and women are the only genders, in this day and age, since some people identify themselves as non-gendered or other gendered. It would be clearer/more accurate if the item was stated as "Out of 100 men and women surveyed..." or "Out of 100 people surveyed, 60 were women and 40 were men."