ferrarih wrote:

In a group of 800 people, 1/5 play at least one instrument, 96 play two or more. What is the probability that one student play exactly one instrument?

A) 2/125

B) 3/125

C)2/25

D) 3/25

E) 1/5

OA:CNo. of Students play 1 instrument +No. of Students play 2 instruments +No. of Students play 3 instruments +...................\(= \frac{1}{5}*800 =160\)

No. of Students play 2 instrument +No. of Students play 3 instruments +No. of Students play 4 instruments +...................\(= 96\)

No of Student play exactly 1 instrument \(= 160-96=64\)

probability that one student play exactly one instrument \(= \frac{64}{800}=\frac{2}{25}\)

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