急问1道PREP！NN救命！

GMATdeJULY

In May Mrs.Lee's earning were 60% of the Lee family's total income. In June Mrs.Lee earned 20percent more than in May. If the rest of the family's income was the same both months, then, in June,Mrs. Lee's earnings were approximately what percent of the Lee familily's total income?

answer:64%

If the rest of the family's income was the same both months这句话是什么意思？

我计算的时候理解成：June+May=0.4 Family, 然后再June=1.2May

但是这样算不出答案？望NN解答！

yunnan1990

5月份，lee的收入占全家收入的60%，六月份Lee的收入比五月份增长了20%，而全家其他人的收入两个月的收入是一样的。那么六月份，Lee的收入占全家收入的百分比大概是多少？

设Lee5月份的收入为0.6x,全家五月份收入是x,其他人的收入是0.4x。

六月份，Lee的收入是，0.6x（1+20%），全家的收入是0.6x(1+20%)+0.4x.

答案是0.72x/1.12x=64%

GMATdeJULY

谢谢2楼NN！

我没看到头俩字，IN MAY啊。。晕

gmatwc

设m1为5月mrs.lee's earning

 m2为6月mrs.lee's earning

根据题意：

In May: m1=0.6t1, 家庭总收入为 t1

In June: m2=m1(1+0.2) , 家庭总收入为 t2

 if the rest of the family's income was the same both months，表达式为：t1-m1=t2-m2

求：m2/t2

根据方程可求出： t2=1.12t1, m2=1.2m1=0.72t1

m2/t2=0.72t1/1.12t1=0.641

有点复杂，楼主批判继承