Question

33. What is the proper way to install a roll of toilet paper: the "over” position, in which the portion you grab hangs over the top of the roll, or the "under" position, in which the portion you grab hangs under behind the roll? A curious student investigated this question by asking a random sample of 10 custodians and a random sample of 50 adults that are not custodians. The table summarizes the results: Custodian Non-Custodian Adult Over 32 Under 2 If one of these individuals is randomly selected, what is the probability that they are a custodian, given that they said "over"?

(A)8/40
(B) 8/50
(C) 8/60
(D) 16:40
(E) 16/100​

Answer 1

Explanation:

8/40

The correct answer is (A). Of the 40 individuals that said that “over” is the correct way to install a roll of toilet paper, 8 were custodians, so the probability is 8/40.