TTGWD 3-18(math)

joanjoans

3-18:

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:

不会做.谁能指点一下?

丁香花儿

我也想知道 啊

joanjoans

有没有常规的,实实在在的解法?

summertao

假设第一年的价格和收入分别为 P1, E1;第二年的价格和收入分别为P2, E2. 根据题意,

P2=(1+k%)P1 and E2=(1+m%)E1

问题是 (P2/E2-P1/E1)/(P1/E1)=?%

解答如下:

把两个等式相除, 得到关系: P2/E2=(1+k%)/(1+m%)* P1/E1,

代入到问题中,得到(k-m)/(100+m),换成百分比,就是D答案了.

joanjoans

谢谢解答。关键是没有看懂问题的意思。