想问一下这道数学题结果是怎么得来的？

eliasfan · 发表于 2011-1-8 14:33:14

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:

eliasfan · 发表于 2011-1-8 14:34:10

答案是D

richard1987 · 发表于 2011-1-8 15:10:11

是不是缺了一个条件啊

eliasfan · 发表于 2011-1-8 15:54:17

缺了什么条件啊？！
Here is the working
Total Revenue = p/100 + (100 -p)1.25/100

r/100 {p/100 + (100-p)1.25/100} = p/100
r (125 - 0.25p) = 100p
r = 100p/(125 - 0.25p)
= 400p(500 - p)
这是网上的答复
但是个人觉得不妥

eliasfan · 发表于 2011-1-8 21:56:20

UP

对于GWD的部分答案很是不解

lillypool · 发表于 2011-1-8 23:55:19

Total Revenue = p/100 + (100 -p)1.25/100

r/100 {p/100 + (100-p)1.25/100} = p/100
r (125 - 0.25p) = 100p
r = 100p/(125 - 0.25p)
= 400p(500 - p)

卖p%的是B报纸啊！为什么p%乘以的是A报纸的单价（1美元）？？
方法是没错，但是数字有问题。
是不是题目给错了？P%应该是A报纸卖的份额？？

eliasfan · 发表于 2011-1-9 09:51:56

我也搞不懂，这是GWD试题里的答案，几乎每套试题都有这么1~2题让自己感觉很纠结的

eliasfan · 发表于 2011-1-9 20:14:39

NN们帮我看看啊？
怎么还是不懂啊？

想问一下这道数学题结果是怎么得来的？

所属分类: GMAT考试

正在浏览此版块的会员 ()