Question

A family has two children. Find the probability that both of them are boys if it is known that at least one of them is a boy.

Answer 1

Let B = Boys, G = Girls

(sample space) S = {BB, GB, BG, GG}

n(S) = 4

Let E = Event of both are boys

F = Event of at least one boys

then E = {BB}, F = {BB, GB, BG}