惭愧，解不出答案（已解决）

leogm

Q28:

Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day.  If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper B, which of the following expresses r in terms of p?

A.    100p / (125 – p)

B.     150p / (250 – p)

C.     300p / (375 – p)

D.    400p / (500 – p)

E.     500p / (625 – p)

Answer: D

请问是如何得出这个答案的？

[此贴子已经被作者于2008-5-17 8:41:56编辑过]

shaan

关键是第二句话理解清楚，r表示的是金额，p表示的是数量。列出两个式子，一加相约即可。

leogm

店内收入的r%来源于A，销量的p%来源于B。是这个意思吗？能否请shaan列一下式子，是怎么得到答案的？谢谢！

sunbocheng

个人觉得题目可能错了 如果P代表的不是newspaper B而是A 那么按照步骤能得出答案就是D

生活就是越狱

可能是楼主把题抄错了（或是原题打错了），我看了GWD31中，原体如下：

Q28:

Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day.  If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?

 

A.     100p / (125 – p)

B.     150p / (250 – p)

C.     300p / (375 – p)

D.     400p / (500 – p)

E.      500p / (625 – p)

Answer: D

注意，只有一处错了（我已标出），然后按照步骤做，就是D了。

leogm

看样子是题目错了，我是复制粘贴的。自己无论如何也算不出上面的答案。如果改为newspaper A，确实就可以了。谢谢楼上的各位。