Question

A couple wants to have 3 children. What is the probability they have at least 1 boy? PLEASE write down each step and show how you got your answer. Also explain each step.

Answer 1

As a child ie equally likely to be a boy or a girl.

So probability of a child to be boy is 0.50

Now there are three children and among them we have to find probability that at least one is boy, that is either there are two girls and one boy, or two boys and one girl or all the three are boys.

This event is the complement of the event that all three are girl.

Now probability that all three are girls is (1-0.5)^3=0.125

Hence the required probability that at least one is boy is

1-0.125 =0.8750