一道概率题！总是做不对！

Xiaotongdi · 发表于 2011-4-17 15:49:16

If a committee of 3 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?

A.20
B.40
C.50
D.80
E.120
这题总共C3,10 然后后面还要减去什么？

892539 · 发表于 2011-4-17 16:14:29

减去5*8 五对儿里选一对儿再乘以剩下八个人中的一个

Xiaotongdi · 发表于 2011-4-17 16:31:29

那就是什么意思啊？

ffen · 发表于 2011-4-17 16:38:02

减去C(5)1*C(8)1
即，先从5对夫妇中选1对出来，剩下一个人从剩下的8人中随便选。

huxleyxu · 发表于 2011-4-17 16:39:49

减去不符合条件的数量，就像楼上大哥说的5*8

一道概率题！总是做不对！

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