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标题: GWD-5-5 [打印本页]

作者: xiongluanyu    时间: 2005-11-3 06:50     标题: GWD-5-5

Q5:

From a group of 3 boys and 3 girls, 4 children are to be randomly selected. What is the probability that equal numbers of boys and girls will be selected?

A 1/10

B 4/9

C 1/2

D 3/5

E 2/3

请问一下,怎么思考呢?谢拉!


作者: daoying    时间: 2005-11-3 19:00

C(3,2)*C(3,2)/C(6,4)=3/5
作者: equilibrium    时间: 2005-11-4 06:47

三男三女,随机取四个人.问男孩女孩相等的可能性. 那就是 两男两女/随机取四个

(C2/3*C2/3) / C4/6 = 3/5


作者: xiongluanyu    时间: 2005-11-6 21:24

谢谢楼上两位 !!!!




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