求教数学一题

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

题目似乎有错，在GWD中的题目是：

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:

这样，答案就容易找了