Official Guide Explanation:
Problem Solving #11

 

 

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Quantitative Review (2nd ed.). Click the links on the question number, difficulty level, and categories to find explanations for other problems.

These are the same explanations that are featured in my "Guides to the Official Guide" PDF booklets. However, because of the limitations of HTML and cross-browser compatibility, some mathematical concepts, such as fractions and roots, do not display as clearly online.

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Solution and Metadata

Question: 11
Page: 63
Difficulty: 4 (Moderately Easy)
Category 1: Arithmetic > Properties of Integers > Factors and Multiples

Explanation: The difference between 12 and 96 is 96 - 12 = 84. So, in 84 numbers, there should be (84/4) = 21 multiples of 4. However, the word "inclusive" tells us that there's one more number, and since the endpoints are both multiples of four, we know that the one extra number is also a multiple of 4, giving us a total of 22, choice (B).

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