|
The Quantitative Comparison format is one of two basic ones used for GRE Quantitative (math) questions. This page lists key features of GRE Quantitative Comparison questions. It also provides the test directions for this question format, a sample question (along with a tip for answering it), and a detailed analysis of the sample.
GRE Quantitative Comparison — Format, Skills Tested, and Test Directions
Here are the key "specs" for GRE Quantitative Comparison questions:HOW MANY: 14 questionsWHERE: In the 45-minute Quantitative Ability section, mixed with Problem Solving questions FORMAT: Multiple-choice (you select one of 4 choices by clicking on an oval) SKILLS TESTED: Your ability to reason quantitatively [list of specific areas covered] DIRECTIONS: The following directions will appear on your screen just before your first Quantitative Comparison question (and you can access them while tackling any Quantitative Comparison question by clicking on the HELP button).
Directions: Each question of this type consists of two quantities, one in Column A and one in Column B. Compare the two quantities and indicate:- if the quantity in Column A is greater
- if the quantity in Column B is greater
- if the quantities are equal
- if the relationship cannot be determined from the information given
In some questions, additional information pertaining to one or both of the quantities to be compared is centered above the two columns.
Any symbol appearing in both columns represents the same thing in one column as in the other.
All numbers used are real numbers.
To review these directions for subsequent questions of this type, click on HELP. |
Sample Quantitative Comparison Question
The following question is typical of GRE Quantitative Comparison questions, although this one is more difficult than average; about 40% of GRE test testers would answer it correctly. Notice that this sample question includes centered information (above Column A and Column B) that applies to both of the quantities to be compared.
| * b < a < -1* | | Column A a2 - b2 | Column B (3a + 3b)(2a - 2b) | |
Quick Tip for Sample Question
In handling GRE Quantitative Comparison questions, you can sometimes manipulate one or both expressions to reveal the comparison. In this question, try factoring both quantities. (The expression in Column A is one of the test-makers' favorites: the difference of two squares.)
Analysis of Sample Question
To reveal the comparison, first express Quantity A in its factored form:(a + b)(a – b) Notice the similarity between this expression and the one in Column B. Now factor out the constants (numbers) in Quantity B so that Quantity B more closely resembles Quantity A: (3a + 3b)(2a – 2b) = 6(a + b)(a – b) = 6(a2 - b2) Now consider the centered information: b < a < –1 In light of this information, (a2 – b2) must be a negative number. Multiplying a negative number by 6 yields an even smaller number (to the left on the real number line). Therefore:6(a2 – b2) < a2 – b2 Quantity A must be greater than Quantity B. The first response is the correct one.
|
|
|
