Official Guide Explanation:
Problem Solving #10

Background

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Solution and Metadata

Question: 10
Page: 63
Difficulty: 3 (Very Easy)
Category 1: Arithmetic > Percents > other
Category 2: Word Problems > Other >

Explanation: This question is a bit involved because of all the talk of prime numbers, but it's essentially asking: what percent of 10 million is 664,579? Additionally, you don't need to worry about the last few digits: all of the answer choices are no more detailed than 660,000. To find the answer, put the percent in fraction form: ((660,000)/(10,000,000)). Cancel out four zeros from the top and bottom of the fraction: (66/(1,000)) = ((6.6)/100) = 6.6%, choice (D).

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