Question

A couple has 2 children. Find the probability that both are boys, if it is known that 

(i) One of them is a boy 

(ii) The older child is a boy.

Answer 1

Sample space = {B₁B_2, B₁G₂, G₁B₂, G₁G₂},

B₁ and G₁ are the older boy and girl respectively.

Let    E₁ = Both the children are boys;

     E₂ =  One of the  children is a  boys;

    E₃ = The older child is a boy