McGraw-Hill Education GRE 2019

However, the test-makers will throw nuances at you that will force you to test

other types of numbers. The following is a list of other types of numbers you

should consider when plugging in numbers in Quantitative Comparisons:

■ Numbers less than −1

■ Numbers between −1 and 0 (i.e., negative proper fractions)

■ Numbers between 0 and 1 (i.e., positive proper fractions)

■ Numbers greater than 1

Though it might seem like plugging in so many different values will be time-

consuming, it’s important to remember the following:

■ You only need to find one contradictory relationship to prove Choice D.

■ Many Quantitative Comparison questions provide constraints on the

variables that will eliminate some of the types of numbers mentioned

previously.

x is an integer

QUANTITY A QUANTITY B

A B C D

SOLUTION: Let x = 1. When x = 1, the value of Quantity A will be 2^1 = 2, and

the value of Quantity B will be (−1)^1 = −1. In this case, the value of Quantity

A is greater, so the answer must be A or D. Now plug in a new value for x.

Since x is an integer, you cannot choose a fraction. A smart number here

would be the strangest-behaving integer: 0. When x = 0, the value of

Quantity A will be 2^0 = 1, and the value of Quantity B will be (−1)^0 = 1. In

this case, the values of the two quantities are equal. Since different values

give different relationships between the quantities, the relationship cannot be

determined. The answer is Choice D.

Strategy: Make Comparisons, Not Calculations

When doing Quantitative Comparison questions, it is essential to step out of the

problem-solving mind-set that you’re accustomed to. Quantitative Comparison

questions are designed to test mathematical intuition and quick, efficient

mathematical reasoning, and this fact should dictate your approach. One key

consequence of this fact is that you should always look at both columns before you

begin any calculations. In many situations, doing so will help you reduce or even

completely avoid any calculations. Look at the following examples:

QUANTITY A QUANTITY B

A B C D

2 x (−1)x

0.98(576) 0.92(574)

164 PART 3 ■ GRE QUANTITATIVE REASONING

02-GRE-Test-2018_107-172.indd 164 13/05/17 11:06 am