Source: Official Guide for the GMAT 13th Ed. Problem Solving; #198 Official Guide for the GMAT 2015 14th Ed. Problem Solving; #198


Last Sunday a certain store sold copies

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 newspaper that day, If r percent of the store's revenue 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?

3 Explanations


bikash pant

why did we take total revenue in denominator?

Sep 29, 2018 • Comment

David Recine, Magoosh Tutor

Because we're looking for a percentage of the total revenue. And to figure out which percentage one number is of another, you divide the percentage number by the total number, turn the resulting fraction into a decimal, and convert the resulting decimal into a percent.

To give a simpler example, suppose your total revenue for selling all newspapers was $10, and your revenue for newspaper A sales was $5.

To figure out what percentage of revenue came form selling newspaper A, you'd want to divide newspaper A revenue by the total:

5/10= 1/2 = 0.5 = 50%

And $5 is 50% of 10, right? :)

Oct 3, 2018 • Reply


Abhinav Mahapatra

In the end of the sum, when finding the ratio, why was 4NP/100 used as numerator instead of NP/100? Isnt NP/100 revenue generated from newspaper A? Please clarify, Thanks.

Aug 16, 2016 • Comment

Sam Kinsman, Magoosh Tutor

Actually, Mike used 4NP/400 as the numerator (and not 4NP/100).

Note that 4NP/400 is the same as NP/100 (just cancel the 4s). So both of these expressions represent the revenue generated from newspaper A. Mike just chose to use 4NP/400 because it's easier to work with.

Sep 2, 2016 • Reply


Gravatar Mike McGarry, Magoosh Tutor

Dec 28, 2013 • Comment

Add Your Explanation

You must have a Magoosh account in order to leave an explanation.

Learn More About Magoosh

Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 13th Ed.

Nova's GRE Prep

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.

Section 5.3 Problem Solving

Section 5.3 Problem Solving

Improve Your Score

Magoosh GMAT is an affordable online course for studying the GMAT.

Learn More About Magoosh

Share Post