CHAPTER 17

Math Formulas on the GMAT

1. If the average (arithmetic mean) of x, 25, y, and 30 is x + y, which of the following equals the value of x?
   1. 
   2. 
   3. 
   4. 
   5. 

Above is a typical Problem Solving question dealing with a commonly tested math formula. In this chapter, we’ll look at how to apply the Kaplan Method to this question, discuss the common math formulas tested on the GMAT, and go over the basic principles and strategies that you want to keep in mind on every Quantitative question involving math formulas. But before you move on, take a minute to think about what you see in this question and answer some questions about how you think it works:

• What math formula is being tested in this question?
• What does the format of the answer choices tell you about your task?
• What can you infer about how the GMAT constructs questions based on common math formulas?
• What GMAT Core Competencies are most essential to success on this question?