HMMT 二月 2000 · POW 赛 · 第 15 题
HMMT February 2000 — POW Round — Problem 15
题目详情
- Ho w man y w a ys an a lass of 10 studen ts b e divided in to t w o groups of 3 and 1 group of 4?
解析
- This is partitioning 10 in to 3 partitions, 2 of 1 t yp e and one of the other. Th us, the 10! answ er is = 2100 . 3!3!4!2!