推 minie:感謝您!! 09/28 19:58
※ 引述《minie (散落在我手中的是溫柔)》之銘言：
: gwd04-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
: ANS:B
: 先謝謝各位的指導~
假設1997, 1998, 1999年的collected rent分別是r7, r8, r9
由題目可知r8=(1+x%)r7
r9=(1-y%)r8
所以r9=(1+x%)(1-y%)r7=[1+(x-y)%-xy%%]r7
題目就是在問1+(x-y)%-xy%%是否大於1，也就是(x-y)%-xy%%是否大於0
條件1 不知道xy的大小如何，無法判斷
條件2 (x-y)%-xy%% = (x-y-xy%)% = (x-y-xy/100)% >0 所以答案B
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