Last Sunday a certain store sold copies of Newspaper \(A\) for \($1.00\) each and copies of Newspaper \(B\) for

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Sun Aug 15, 2021 8:17 am

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. \(\dfrac{100p}{125-p}\)

B. \(\dfrac{150p}{250-p}\)

C. \(\dfrac{300p}{375-p}\)

D. \(\dfrac{400p}{500-p}\)

E. \(\dfrac{500p}{625-p}\)

Answer: D

Source: Official Guide

If you're not sure how to proceed with this question, or if you're behind on time and you want to catch up, you can give yourself a 50-50 chance in about 20 seconds.

To do so, we'll see what happens when we use an EXTREME value for p.
Say p = 100
In other words, 100% of the newspapers sold were Newspaper A.
This means that 100% of the revenue is from Newspaper A.
In other words, when p = 100, then r = 100

At this point, we'll plug in 100 for p and see which one yields a value of 100.
Only answer choices B and D work.
B) 150(100)/(250-100) = 100 PERFECT
D) 400(100)/(500-100) = 100 PERFECT

Now take a guess (B or D) and move on.