17版 OG 数学168题

Ly2016 · 发表于 2017-5-5 12:11:40

A couple decides to have 4 children .if they succeed in haveing 4 children and each child is equally likely to be a boy or a girl,what is the probability that they will have exactly 2 girls and 2 boy?
这道题大家有没有什么好的解法呢？求回复

chaewoosim · 发表于 2017-5-5 12:33:50

4次里面选2次生男孩，就是C4,2，然后每次生男生女的概率都是0.5，那么就是C4,2*0.5^4

17版 OG 数学168题

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