Problem 3. A group of n 2 1 tourists come to a restaurant and sit around several round tables (it is possible for a table to have only one person). Then each (nonempty) table orders one of 7" possible drinks. Prove that the number of ways this can happen is r(r+1)(r+2)...(r+n1), Where two outcomes are the same if each person has the same left neighbor (possibly the same person) and the same drink in both of them