gmatprep 2 - ps probability question

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gmatprep 2 - ps probability question

by gmatjoe » Sat Feb 16, 2008 9:09 am
Hi there, can anyone solve this one (it feels like a standard question but I get stuck):

Q: In a survey of 248 people, 156 are married, 70 are self-employed and 25% of those married are self-employed. If a person is randomly selected from those surveyed, what is the probability that the person selected will be self-employed but NOT married.

a) 1/8
b) 4/31
c) 117/248
d) 1/4
e) 31/117

I ended up guessing e). Correct answer is a).

Many thanks in advance.

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by praso » Sat Feb 16, 2008 9:27 am
25% of 156 married ppl are self employed ; which is 39.

70-39 = 31 are self employed and un-married.

probablity of picking self employed but not married is 31/248 =1/8 :)

Junior | Next Rank: 30 Posts
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by gmatjoe » Sat Feb 16, 2008 10:08 am
thanks. indeed. i got stuck at 31/248, not realizing that this is 1/8...