a You ask a coworker if she has any children She says yes tw

(a) You ask a co-worker if she has any children. She says yes, two ages, 3 and 9, the oldest is a boy. What is the probability that both her children are boys.

(b) Interpret your answer (the number that you calculated for the above probability)

Solution

The probabiltiy of a girl child or a boy child is equally likely. So

P(boy)=P(girl)=0.5

(a)

Since child are independent from each other so

P(both are boy)=P(oldest is boy)P(youngest is boy)=0.5*0.5=0.25

(b)

If a family has 2 children, then there is 25% chance both are boy.