求助 GWD8-29

wangjianghua

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

答案给的B.  我觉得是不是应该选D啊？  请牛人指点，谢谢

wangjianghua

thanks&nbsp; a&nbsp; lot&nbsp; !!!!!!

creditadvices

如果传说说得对，可考场上来不及这么认真，我觉得：题里没有说X，Y必须为正值，所以，漏洞多多，A必然错。

而且这题是考全世界的，要知道全世界的傻瓜多多啊！每道题都设置两三重障碍，那傻瓜还不疯了？

rosemarys

设1997年为A,98年为B,99年为C,则根据已知条件可以写成:

(1)(B-A)/A=X%--->A=B/(1+X%)

(2)(C-B)/B=-Y%--->C=(1-Y%)B

求(C-A)/A的正负

即求[(1-Y%)B-B/(1+X%)]/[B/(1+X%)]=(X-Y)/100-(XY/100)

条件(2)可好可以求解.但条件(1)只能知道(X-Y)的正负,但没办法判断与XY

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