Question
A couple has two children,
Find the probability that both children are males, if it is known that at least one of the children is male.
Solution
S = {MM, MF, FM, FF}
where M stands for male and F stands for female
Let A: both the children are males
and B: at least one of the children is male.
A = {MM}, B = {MM, MF, FM}
Required probability = 
