作者catspace (柏拉图的永恒...)
看板GMAT
标题Re: [问题] Please help a "vegetable bird" like me
时间Fri Sep 12 21:03:25 2008
※ 引述《RainySunDay (Heart fly)》之铭言：
: 1.How many different 6-letter sequences are there that consist of 1 A, 2 B's,
: and 3 C's?
: A:60
不就是不尽相异物的排列吗?
6!
----- = 60 #
2!3!
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※ 发信站: 批踢踢实业坊(ptt.cc)
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1F：推 RainySunDay:Thanks, but more explanation could be better,ha ha 09/13 01:45
2F：推 windton:在统计学里，这有点像是公式的东西吧，可以背一下^^ 09/13 02:36