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## Official Guide Explanation:

Problem Solving #3

**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.

Click here for an example of the PDF booklets. Click here to purchase a PDF copy.

**Solution and Metadata**

**Question****: 3**

Page: 62

Difficulty: **3** (Very Easy)

Category 1: Algebra > Equations >

Category 2: Word Problems > Other >

**Explanation:** If Mario was 32 years old 8 years ago, he's 40 now. x years ago, he was x years younger, so his current age is 40 - x. If you're not sure about how to apply that x, substitute a number for it: if you think about the arithmetic you do when you wonder, "how old was he 5 years ago," it may help clarify what to do with x.

Click here for the full list of GMAT Quant Review explanations.

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Total GMAT Math
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