涛涛数学第四套28

redhead

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)

答案是D，怎么算的？

虽然猜对了，但是还是不知道怎么算。

sunbocheng

可能题目错了 P代表newspaper A的话能算出D这个答案 前面有一位提过这个问题

redhead

我说呢, 我也觉得,不然根本算不出来