Official Guide Explanation:
Problem Solving #D06

Background

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Solution and Metadata

Question: D06
Page: 21
Difficulty: 6 (Moderately Difficult)
Category 1: Arithmetic > Sets > 2 sets
Category 2: Word Problems > Sets >

Explanation: If there are 200 households surveyed and 80 used neither brand, the remaining 120 households used either A only, B only, or both. 60 used only A, leaving 60 that used either B only, or both. We next learn that for every household that used both, 3 used only B. Thus, of the remaining households, one - fourth used both, and the other three - fourths used only B. Of the remaining 60, that means 15 used both, and 45 used only B. Choice (A) is correct.

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