# Math Book 2: Ratio, Proportion

GMAT® Prep : Ratio, Proportion, and Variation

You will get one to three questions from ratio, proportion and variation in the GMAT quant section - in both variants viz., problem solving and data sufficiency. The concepts tested include simple ratio questions, direct proportion, inverse proportion, partnership, mixtures and rule of alligation. A relatively easy topic.

### Concepts Covered

Ratio Proportion Variation is a fundamental quant topic tested in the GMAT Math section. Many word problems in the problem solving section of GMAT Math section are essentially ratio proportion questions. Wizako's GMAT Math Review Book covers the following concepts in this chapter:

1. The meaning of the term ratio and an illustrative example to explain the same.
2. Relation between ratios and expressing a ratio as a fraction.
3. Definition and explanation of the term proportion and continued proportion.
4. Concept and illustration of direct variation and inverse variation.
5. Partnership and profit sharing.
6. 30 solved examples with explanation that helps understand the topic better, some of which include "must know" short cuts that would save time in arriving at the solution as and where applicable.
8. A multiple choice test comprising 60 GMAT level questions in the workbook. All questions are provided with explanatory answers.

Here is a typical solved example from this chapter.

### Sample Question

What is the value of 'x' if it is the mean proportional of x - 4 and x + 8?

x is the mean proportional of x - 4 and x + 8 means x - 4 : x :: x : x + 8

Therefore, $$frac{x - 4}{x}$ = $\frac{x}{x + 8}$ Or x2 =$x - 4)(x + 8)
x2 = x2 + 4x - 32

Therefore, x = 8

### Chapterwise details of Wizako's Math Lesson Books

Math Lesson Book 1

 1 Linear Equations Details 2 Quadratic Equations Details 3 Set Theory Details 4 Sequences & Series Details 5 Number Properties & Theory Details 6 Inequalities Details 7 Functions

Math Lesson Book 2

 1 Descriptive Statistics Details 2 Ratio Proportion Details 3 Mixtures 4 Interest 5 Rates: Speed Distance Details 6 Rates: Races Details 7 Rates: Work Time Details

Math Lesson Book 3

 1 Percents Details 2 Profits Details 3 Permutation Combination Details 4 Probability Details 5 Geometry Details 6 Solid Geometry 7 Coordinate Geometry Details