请教一道TAOTAO数学--Math3-18

Q18:

Last year
the price per share of Stock X increased by k percent and the earnings per
share of Stock X increased by m percent, where k is greater than m.  By what percent did the ratio of price per
share to earnings per share increase, in terms of k and m?

A.      k/m %

B.       (k-m) %

C.      [100(k-m)]/(100+k) %

D.      [100(k-m)]/(100+m) %

E.       [100(k-m)]/(100+k+m) %

Answer: D

Why？？

路过。顺手解答一下，以前也掉进过这道题的陷阱~~

这道题解题关键是看懂问题的题干，要是把问题翻译成chin-english，估计你就会解答了~~~

 the ratio of (price per share to earnings per share )increase  by what percent ?

设增长前the price per share of Stock X=P，the earnings per share of Stock X=E, 设增长前ratio=R1=P/E

则有增长后the price per share of Stock X=P（1+k%),the earnings per share of Stock X=E(1+m%),增长后ratio=R2=[P（1+k%)]/[E(1+m%)]

求【(R2-R1)/R1】*100%，把R1，R2代入化简得答案D。

感觉做这类题一定要多读几遍问题，尤其对修饰关系要理清楚，一些限定词和定语从句要读懂，才能正确把握所求的量。

不知道说明白了没有，呵呵~~

找一些类似的题目集中训练训练就不会怵了。按hang13的说法就是题海战术，我觉得很有道理，熟能生巧，也能训练对问题的敏感度，把握到出题者的思路，但是大量做题以后一定要及时总结~~~祝你好运！