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难题请教,各位给参详一下!

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楼主
发表于 2009-11-7 08:23:56 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
Town T has 20000 residents , 60 percent of whom are female . What percent of the residents were born in Town T ?

(1) The number of female residents who were born in Town T is twice the number of male residents who were not born in Town T.

(2) The number of female residents who were not born in Town T is twice the number of male residents who were born in Town T .



假设born female占总人数百分比:x ,born male:y ;求x+y?

(1)20000*x=2*(20000*(1-0.6-y))  =>  x+2y=0.8

(2)  20000*(0.6-x)=2*20000*y  => x+2y=0.6

本体应该无解吧,答案却是有解,是我理解题目有问题吗?
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沙发
发表于 2009-11-7 08:54:11 | 只看该作者
我跟你的思路一样哦,怎么回事?
板凳
发表于 2009-11-7 10:07:40 | 只看该作者
同问
地板
发表于 2009-11-7 11:32:38 | 只看该作者
我也觉得是啊。。。
请nn解答下~~谢谢!
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