posted by Nicole .
Assume the probability is 1/2 that a child born is a girl. If a family has three children, what is the probability that they have a) exactly one girl b) at most two boys?
a) So it could be
GBB or BGB or BBG
prob of that is 3(1/2)(1/2)(1/2) = 3/8
b) at most 2 boys ---> cannot have BBB
which has a prob of 1/8
so your case has prob of 1 - 1/8 = 7/8