难题请教，各位给参详一下！

JohnDong

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？

loveyj613

我也觉得是啊。。。
请nn解答下~~谢谢！

verylotus

同问

zhaoke27

我跟你的思路一样哦，怎么回事？