In how many ways can a pack of 52 cards be divided in 4 sets, three of them having 17 cards each and fourth just 1 card?
First we divide 52 cards into two sets which contains 1 and 51 cards respectively is
52!1!51!
Now 51 cards can be divided equally in three sets each contains 17 cards. Here order of sets is not important 51!3!(17!)3 ways.
Hence the required number of ways
=52!1!51!×52!3!(17!)3
=52!1!3!(17)3=52!(17!)33!
Alternate Method= First set can be given 17 cards out 52 cards in 52C17. Second set can be given 17 cards out of remaining 35 cards (i.e. 52-17=35) in 35C17. Third set can be given 17 cards out of remaining 18 cards (i.e., 35-17=18) in 18C17 and fourth set can be given 1 card out of 1 card in 1C1. But the first three sets can be interchanged in 3! ways. Hence the total number of ways for the required distribution.
=52C17×35C17×18C17×1C1×13!
=52!17!35!×35!17!1!×18!17!18!×13!
=52!(17!)33!