GMAT Book 2: Ratio, Proportion & 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.

Syllabus Covered in Wizako's GMAT Book

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.
7. 19 exercise problems with the answer key and explanatory answers.
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 in Wizako's GMAT Book from this chapter

Sample Question

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

Explanatory Answer

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

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