Arithmetic Ability
 Probability

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Q.

One lady has 2 children, one of her child is boy, what is the probability of having both are boys ?

View Answer

Correct choice: A

Explanation:

In a family with 2 children there are four possibilities: 1) the first child is a boy and the second child is a boy (bb) 2) the first child is a boy and the second child is a girl (bg) 3) the first child is a girl and the second child is a boy (gb) 4) the first child is a girl and the second child is a girl (gg) But already given that one child is boy. So we have three possibilities of (bb)(bg)(gb). n(E)= both are boys=BB=1 n(S)= 3 Required probability P = n(E)/n(S) = 1/3.
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