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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

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

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

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