Suppose of men and of women have grey hair. A grey-haired person is selected at random. What is the probability of this person being male? Assume that there is an equal number of males and females.

Let MG : Men having grey hair
WG: Women having grey hair
G: Having grey hair
Given an equal number of males and females. So let’s assume both the probability be
We want to find , i.e. probability of a randomly selected grey person to be male

Therefore, the probability of a randomly selected grey person to be male is