Statistics And Probability Question 297

Question: In a certain town, 40% of the people have brown hair, 25% have brown eyes and 15% have both brown hair and brown eyes. If a person selected at random from the town, has brown hair, the probability that he also has brown eyes, is

[MNR 1988]

Options:

A) $ \frac{1}{5} $

B) $ \frac{3}{8} $

C) $ \frac{1}{3} $

D) $ \frac{2}{3} $

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Answer:

Correct Answer: B

Solution:

  •          $ P(A)=\frac{40}{100}, $   $ P(B)=\frac{25}{100} $  and  $ P(A\cap B)=\frac{15}{100} $                  So  $ P( \frac{B}{A} )=\frac{P(A\cap B)}{P(A)}=\frac{15/100}{40/100}=\frac{3}{8}. $