In how many ways can we distribute 13 pieces of identical candy to 5 kids, if the two youngest kids are twins and insist on receiving at least four pieces each?
The two youngest kids have four pieces each. That leaves 5 pieces to distribute to 5 kids. Each piece of candy can go to any of the 5 kids, so 5^5, or 5*5*5*5*5, or 3125 ways.