GMAT Quantitative Section:
Prep Tips for Data Sufficiency Questions

Data sufficiency questions are part of the 75-minute quantitative section. There are 13 or 14 of these questions mixed in with 23 or 24 problem solving questions.

The purpose of data sufficiency questions is:

Can you answer the question with the information provided?

Getting Started with Data Sufficiency Questions

Most people have trouble with data sufficiency questions because they are unlike math questions on other tests. After you learn the format and structure, you will discover that they are not so difficult.

First, memorize the structure and format of the questions. Specifically,

  • Every single data sufficiency question lists the exact same answers. You should practice with GMAT tests so much that you never have to look at the answer choices.
  • At first, you will stumble over the format and not even be dealing with the question. Nail the format and the the questions will not seem so odd, or difficult.
  • You should never waste time reading the instructions for any section of the GMAT. This is particularly important for this section because the instructions are somewhat convoluted and long.

Keep practicing Practice a lot. You will master the data sufficiency section and increase your test-taking speed.

Bottom line for data sufficiency questions:  Know the Test!

Really Simple Example Data Sufficiency Question

To illustrate how odd data sufficiency question are, I made up the following question by changing the words of an actual old GMAT question (in order to not violate any copyrights).
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A. Statement (1) ALONE is sufficient, but statement (2) ALONE is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) ALONE is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

Prep Tips for Data Sufficiency Questions

Look at the question and identify what specific info you need to answer the question.

Do not assume anything beyond what is explicitly stated in the question,

Eliminate any answer choices that you can. If you cannot figure it out and need to guess the answer, the fact that you reduced the number of possible answers greatly increases your odds of guessing right.

Get a study guide for the quantitative section or a general book on improving your math skills if you are weak in math or intimidated by it. It will help you immensely.

Instructions For Data Sufficiency Questions

These are the instructions you should know backwards and forwards so you never have to waste valuable test time reading them.
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.

Be sure to learn these and never have to read them during the test, or even slow down to think about the mechanics of the question.