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GMAT Data-Sufficiency Questions — Format, Directions and Example Question

This page lists the key features of the GMAT Data-Sufficiency format, one of two basic formats for GMAT Quantitative (math) questions. It also provides the test directions for this question format, an example question, and a detailed analysis of the example.

Data Sufficiency — Format, Skills Tested and Directions

Here are some key facts about the GMAT Data-Sufficiency format:

How many: 13-14 questions

Where: In the 75-minute Quantitative section, mixed with Problem-Solving questions

Format: Multiple-choice. A question is followed by two numbered statements, which provide specific information. You select one of 5 choices by clicking on an oval. The 5 answer choices are the same for every Data-Sufficiency question.

Skills tested: Your ability to understand arithmetic, algebra, and geometry concepts, and your ability to reason logically about quantitative problems

Directions: The following directions will appear on your screen just before your first Data-Sufficiency question (and you can access them while tackling any Data-Sufficiency question by clicking on the HELP button):

Directions: This problem consists of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether:

statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked;
statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked;
BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient;
EACH statement ALONE is sufficient to answer the question asked;
statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

Numbers: All numbers used are real numbers.

Figures: A figure accompanying a data sufficiency problem will conform to the information given in the question, but will not necessarily conform to the additional information in statements (1 and 2).

Lines shown as straight can be assumed to be straight and lines that appear jagged can also be assumed to be straight.

You may assume that positions of points, angles, regions, etc., exist in the order shown and that angle measures are greater than zero.

All figures lie in a plane unless otherwise indicated.

Note: If the data sufficiency problem asks you for the value of a quantity the data given in the statements are sufficient only when it is possible to determine exactly one numerical value for the quantity.

To review these directions for subsequent questions of this type, click on HELP.

Note that figures (visuals) accompanying Data-Sufficiency questions are not necessarily drawn to scale (unless the question at hand indicates that a figure is drawn to scale).

The Data-Sufficiency Format — Example Question

Following is a typical GMAT Data-Sufficiency question. Notice that the five answer choices essentially restate a portion of the directions. As with Problem-Solving questions, you select an answer choice by clicking on a button to its left, and you deselect a choice by clicking on another one.

Are the majority of salespeople employed by XYZ Company commissioned?

The number of salespeople employed by XYZ Company exceeds the number of employees at XYZ Company who are not salespeople.
The percentage of XYZ Company's salespeople who are commissioned exceeds the percentage of employees at XYZ Company who are salespeople.

Statement 1 ALONE is sufficient to answer the question, but statement 2 alone is NOT sufficient.
Statement 2 ALONE is sufficient to answer the question, but statement 1 alone is NOT sufficient.
BOTH statements 1 and 2 TOGETHER are sufficient to answer the question, but NEITHER statement ALONE is sufficient.
Each statement ALONE is sufficient to answer the question.
Statements 1 and 2 TOGETHER are NOT sufficient to answer the question.

Quick Tip for Example Question

Ask yourself what specific information you need in order to answer the question posed. As you consider each of the two numbered statements independently of each other, ask yourself whether the statement provides any such information.

Analysis of Example Question

This problem involves the concept of proportion. During the GMAT, expect to encounter at least two proportion questions (either Problem Solving or Data Sufficiency) altogether. Notice that no arithmetical calculations are required here. That's because Data-Sufficiency problems are designed to test you primarily on concepts, not on your ability to solve a problem by working to a quantitative solution. (That's what Problem-Solving questions are for.)

In order to answer the question posed here, you need information about the number of commissioned salespeople relative to the number of non-commissioned salespeople. Statement (1) alone provides no such information. [You can eliminate the first and fourth answer choices (A and D).]

Statement (2) alone provides a meaningless comparison between percentages of two different "wholes"; the statement provides no information about the number of commissioned salespeople relative to the number of non-commissioned salespeople (the "whole" being the total number of salespeople). Thus, statement (2) alone is insufficient to answer the question. [You can eliminate the second answer choice (B).]

Considered together, however, statements (1) and (2) do suffice to answer the question. The correct response is the third answer choice. Statement (1) provides that more than 50% of the employees are salespeople. Statement (2) adds that this percentage is less than the percentage of salespeople who are commissioned. Thus, the percentage of salespeople who are commissioned must exceed 50%, and the answer to the question itself must be "yes." (In other words, you can answer the question considering the two statements together.)