Statistics And Probability Question 171
Question: A pair has two children. If one of them is boy, then the probability that other is also a boy, is
Options:
A) $ \frac{1}{2} $
B) $ \frac{1}{4} $
C) $ \frac{1}{3} $
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
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Let $ P(A)= $ probability of a boy in two children $ =\frac{3}{4} $ Because cases are $ BB,\,BG,\,GB,\,GG=4 $ Favourable cases are $ BB,\,BG,\,GB=3 $ The probability that the second child is also boy is $ P(A\cap B)=\frac{1}{4} $ We have to find $ P(B/A)=\frac{P(A\cap B)}{P(A)}=\frac{1/4}{3/4}=\frac{1}{3}. $
BETA
