In a family of 7 children the probability that they are all

In a family of 7 children, the probability that they are all girls is 0.78%. What is the probability of at least one boy this family of 7 children?

Solution

probability of having atleast one boy = 1 - (probability of having no boy) = 1 - (probability of having all girls)

= 1 - 0.0078 = 1 - .9922

Ans = 99.22 %