Suppose that 5% of men and 0.25% of women have grey hair. A grey haired person is selected at random. What is the probability of these person being male? Assume that there are equal number of males and females.

Explanation

Let the events M,F and G be define as follows:

M: A male is selected
G: A person has grey hair

It is given that the number of males = the number of females

P(M)=P(F)=1/2

Now, P(G/M)= Probability of selecting a grey haired person given that they are male
=`5%=5/100`

Similarly,
P(G/F)=`0.25%=0.25/100`

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