Question

A family has ninenine children. if this family has exactly threethree boysboysâ, how many different birth and gender orders areâ possible

Answer 1

This is the problem of how many permutations the set bbbgggggg has. The set has size n=9, and you choose p=3 boys.

You can calculate it as:


`\binom{9}{3} = (9!)/(3! \cdot 6!) = (362880)/(6\cdot720) = 84`