Official Guide Explanation:
Data Sufficiency #96

 

 

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.

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Solution and Metadata

Question: 96
Page: 160
Difficulty: 6 (Moderately Difficult)
Category 1: Algebra > Symbolism >
Category 2: Algebra > Inequalities > other
Category 3: Arithmetic > Real Numbers >

Explanation: If the symbol is equal to zero, then x itself must be greater than -1 and less than or equal to 0.

Statement (1) is sufficient: It gives us the range of x, and no matter what x is within that range, the value of the symbol is 0.

Statement (2) is insufficient. If x is 0.25, symbol - x is equal to 1. If x is -0.25, symbol - x is equal to 0. Both values of x are acceptable with this statement but give different answers to the question. Choice (A) is correct.

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