Official Guide Explanation:
Problem Solving #98

 

 

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: 98
Page: 74
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Properties of Integers > Factors and Multiples

Explanation: The greatest common divisor (or factor) of two numbers cannot be larger than the two numbers. In fact, the largest the GCF can be is equal to the smaller of the two numbers, if the smaller number is a factor of the larger number (x = 6 and y = 12, for instance). So, (E) must be correct: since both x and y are positive, x + y must be greater than both x and y, and thus cannot be the GCF.

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