Official Guide Explanation:
Problem Solving #D19

 

 

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Review (12th 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: D19
Page: 22
Difficulty: 4 (Moderately Easy)
Category 1: Geometry > Triangles > Length of sides

Explanation: The limitations on the length of a side of a triangle are that it must be greater than the difference between the lengths of the other two sides, and less than the sum of the lengths of the other two sides. Since two sides of the triangle are 2 and 7, k must be greater than 5 and less than 9. Since k is an integer, the only possible values are 6, 7, and 8. However, the question tells us that k is less than 7, meaning that 6 is the only possibility. Choice (A) is correct.

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