McGraw-Hill Education GRE 2019

Finally, when testing numbers for Quantitative Comparison questions testing

positives and negatives, you should always test at least one negative case and one

positive case. You want to play devil’s advocate, and the best way to do so is by

choosing numbers with different signs.

x > y; xy ≠ 0

QUANTITY A QUANTITY B

x^2 y^2 A B C D

SOLUTION: The even exponents in the quantities should clue you in that the

question might be addressing properties of positives and negatives. Let’s thus

choose positive and negative cases for x and y:

Case 1: x = 3 and y = 2. Quantity A: 3^2 = 9. Quantity B: 2^2 = 4. Quantity A is

greater. The answer is A or D.

Case 2: x = 3 and y = –2. Quantity A: 3^2 = 9. Quantity B: –2^2 = 4. Quantity A

is still greater. Though you might be tempted to stop here and select A, notice

that you have not looked at situations where both values are negative.

Case 3: x = –5 and y = –6. Quantity A: –5^2 = 25. Quantity B: –6^2 = 36. In

this case, Quantity B is greater. A relationship cannot be determined, so the

answer is D.

192 PART 4 ■ MATH REVIEW

03-GRE-Test-2018_173-312.indd 192 12/05/17 11:51 am