Question

一道GMAT数学题~我看不懂什么意思。。

Amy's grade was the 90th percentile of the 80 grades for her class. Of the 100 grades from another class, 19 were higher than Amy's, and the rest were lower. If no other grade was the same as Amy's grade, then Amy's grade was what percentile of the grades of the two classes combined?

A. 72nd
B. 80th
C. 81st
D. 85th
E. 92nd

答案是D

Answer 1

在 Amy 班那 80 个分数中，90% 比她的分数低。所以有 72 个分数比她的低。在那 100 人的班里，有 81 个比 Amy 的低。（注意：是 81 而不是 80，因为 Amy 不在这个班里面。）两班合起来就有 180 个学生，其中 72 + 81 = 153 个的分数比 Amy 的低。153/180 = 85%，所以 Amy 在这 180 人当中的 percentile 是 85。

Answer 2

楼上说的意思是对的,grade在这题应该翻译成学生的成绩吧