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Official Guide Explanation:Problem Solving #111

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.

Question: 111
Page: 167
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Decimals >
Category 2: Arithmetic > Percents > Percent Change
Category 3: Word Problems > Discount >

Explanation: First, this question will be easier without the decimals. It doesn't matter whether we're talking about forty cents or forty dollars or forty whatever - units, so stick with what's easy. The non - reduced price of two candy bars is 80; the sale price is 75. Percent change is equal to ((difference)/(original)), so in this case it's ((80 - 75)/80) = (5/80) = (1/16). It's helpful to know that (1/16) = 0.0625, but if you don't have that fact in your toolbox, it's easy enough to approximate. You can set up a ratio to find the percent: (1/16) = ((x)/100). Since 100 is a little more than 6(16), x is a little more than 6.

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