Quantitative Comparisons on the GRE Math Test — Practice Questions

By Ron Woldoff, Joseph Kraynak

The GRE Math test contains several Quantitative Comparison questions. These questions cover many different topics, from geometry to algebra, but they are similar in that they always give you the same four answers to choose from:

  • Quantity A is greater.

  • Quantity B is greater.

  • The two quantities are equal.

  • The relationship cannot be determined from the information given.

The following practice questions ask you to calculate whether a probability for a die roll exceeds a certain amount, and whether the area of a parallelogram is greater than a given amount.

Practice questions

Directions: For the following questions, choose from these answer choices:

A. Quantity A is greater.

B. Quantity B is greater.

C. The two quantities are equal.

D. The relationship cannot be determined from the information given.

  1. Two standard six-sided dice are thrown.

    image0.png

  2. In parallelogram ABCD,

    image1.png

    x = 60, AB = 2, and AD = 4

    image2.png

Answers and explanations

  1. A

    Probability comes from the number of desired outcomes divided by the number of possible outcomes. The probability of 6 doubles over 36 total possible combinations is

    image3.png

    which reduces to

    image4.png

  2. C

    To find the area of the parallelogram, multiply the base AD by the height. The base is 4, but finding the height can be a challenge. Draw a line from Point B straight down to AD, creating a 90-degree angle with AD and a 30-60-90 triangle with a hypotenuse of 2 (segment AB). Remember the side relationships of a 30-60-90 triangle: If it has a hypotenuse of 2, then the height is

    image5.png

    which is also the height of the parallelogram. The base times the height produces an area of

    image6.png

    This problem shows why you need to memorize the common Pythagorean ratios. Though you can always find the third side of a right triangle given the other two sides, in this example, you’re given only one side of the 30-60-90 triangle.