boys and girls

albany09 · 发表于 2008-11-12 06:57:00

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

jonathan1987 · 发表于 2008-11-12 07:25:00

答案是3/5吧!

因为一共有6个人,所以分母c64

题目是随机抽2男2女,所以不需要考虑排列的情况. 因此分子是c32*c32

也就是c32*c32/c64了

HannaJia · 发表于 2015-10-21 09:53:03

会了，谢谢

boys and girls

boys and girls

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