回复：请教解数学题。

来源: guest1000 于 2010-09-07 20:04:56 [] [旧帖] [给我悄悄话] 阅读数 : (251 bytes)
回答: 请教解数学题。 由 灰衣人 于 2010-09-06 18:14:36

Here is the easiest way to solve the problem.

Put all 20 balls on a line. There are 19 positions between these 20 balls. If you want to put them in 4 bins without any bin being empty, the number of possibilities is (19 choose 3).

Done.

请您先登陆，再发跟帖！