Answered

Three families each have three sons and no daughters. Assuming boy and girl babies are equally likely, what is the probability of this event?



Answer :

three families with three children all boys 
parents-2
children-3
total-5 times 3= 15
then boys-3 times three=9

Answer: 9/12 
Percentage:75%
AL2006

I don't think it matters how many families are involved. 
You're talking nine live births, and the probability of a
male birth each time is 50% .

So the probability of nine males in nine births is

                 (1/2)^9  =  1/512  =  about 0.195 percent  (rounded)