求助：prep摸考软件中遇到的2道数学问题

In May,Mrs.lee's earnings were 60 percent of the lee family's income.In June, Mrr. lee earned 20% more than in May.If the rest of the family's income was the same both montms,then,in June,Mrs.lee's earnings were approximately what percent of the lee family's total income.

答案是64%

我觉得这道题条件不够，是求不出答案的。。。

还有一题：If 500 is the mutiple of 100 that is closet to x and 400 is the mutiple of 100 that is closest to y, which multiple of 100 is closest to x+y

(1)x<500

(2)y<400

答案是E，这道题连题目也没看懂。。。

4月30日就要考了，希望G友们帮忙解答一下，万分感激

感谢楼上的！！