1. The problem statement, all variables and given/known data We have three groups, group 1 contains 21 people, group two contains 18 people and group 3 contain 50 people. First we need to construct a team of 4 people of three groups. How many ways can such a team be constructed? I use combinate such that it will be calculated in Maple. numbcomb(21+18+50, 4) is number of ways this group can constructed. second question is tricky one. How many ways can the group of 4 be constructed if its a requirement that there must be at least one person from each group in the group of 4 ? 3. The attempt at a solution I know its numbcomb(21+18+50,4) to be used to again. But I am not sure howto proceed. So any hints of help would be apriacated.