Official Guide Explanation:
Problem Solving #94

Background

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Solution and Metadata

Question: 94
Page: 165
Difficulty: 4 (Moderately Easy)
Category 1: Arithmetic > Percents > other
Category 2: Word Problems > Mixture Problems >

Explanation: This is an excellent question to assign a value to the unknown quantity. Say that there are 100 registered voters. That means there are 60 Democrats and 40 Republicans. If 75% of the D's voted for Candidate A, that's 75%(60) = 45. If 20% of the R'd voted for Candidate A, that's 20%(40) = 8. The total number, then, is 45 + 8 = 53. Since the question is looking for a percent, we have to figure out what percent 53 is of the original number; that's what makes 100 such good number to start with: 53 is 53%, choice (B).

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