GWD管卫东 GMAT 第8套 数学第29题 求讲解 但是右上角有个※ 是有争议的意思么?

题目

GWD管卫东 GMAT 第8套 数学第29题 求讲解 但是右上角有个※ 是有争议的意思么?
Q29:
The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998.Was the annual rent collected by the corporation from the building more in 1999 than in 1997?
(1) x > y
(2) xy/100 < x – y
A.Statement (1) ALONE is sufficient,but statement (2) alone is not sufficient.
B.Statement (2) ALONE is sufficient,but statement (1) alone is not sufficient.
C.BOTH statements TOGETHER are sufficient,but NEITHER statement ALONE is sufficient.
D.EACH statement ALONE is sufficient.
E.Statements (1) and (2) TOGETHER are NOT sufficient.

答案

设1997为1, 1998年则为1+x%, 1999年为（1-y%)(1+x%)
题目是要比较1999与1997,也就是（1-y%)(1+x%)与1的大小,两个相减等于
x/100-y/100-xy/10000与0比较大小
两边同时乘以100
得到x-y-xy/100
通过条件2可以得出答案