GMAT – Secrets of Data Sufficiency

Data Sufficiency

The Data Sufficiency (DS) section of the GMAT is considered by many to be the most difficult part of the exam. To do well on the DS section of the GMAT an understanding of how to approach the problems is more important than your ability to solve the problem.

Rather than solving a mathematical equation out right you will be provided a question followed by two statements, which may or may not lead to an answer to the given question. From the two statements given the test taker must establish which (if any) of the statements can be used to solve the problem and in what combination. Choosing the correct answer from the five statements listed.

Remember the format of data sufficiency questions is as follows.

Data Sufficiency Example:

Question: Is x > 4?

Statement 1: x < 9

Statement 2: x is an integer

Possible answers

A)     If statement (1) e questions, but by itself is sufficient to answer the question, but statement (2) by itself is not;

B)      If statement (2) by its self is sufficient to answer the question;

C)      If statements (1) and (2) taken together are sufficient to answer the question, even though neither one is sufficient by itself.

D)     If either statement by itself is sufficient to answer the question;

E)      If statements (1) and (2) taken together are not sufficient to answer the question, requiring more data pertaining to the problem

To do well on these problems it is important to remember a few key points:

• Seemingly difficult questions are often not as tough as they first appear. Test-makers know that questions that appear incredibly hard may cause the harried and overwhelmed test-taker to cave to the temptation to simply choose (E). Therefore if it seems super difficult be wary! Chances are you’re being misled.

• Confusing statements – Remember: you don’t have to read statements #1 and #2 in numeric order. This is a normal unconscious behavior since it mirrors normal reading patterns. However, the best test strategy is to consider the simpler statement before the more difficult one. Doing so can help you eliminate answer choices quickly and increase your chances of guessing correctly, should you be pressed for time.
• Double Jeopardy – As could be expected of such clever people, GMAT writers often provide Statements #1 and #2 that provide identical information (usually in transposed algebraic forms). If you spot this, remember that your answer choices are automatically limited to (D) or (E).

• You don’t have to solve! – A common mistake is to completely solve Data Sufficiency problems. This is a huge waste of time since test-takers are only required to evaluate whether a problem is solvable given the provided statements. Instead of solving DS questions like normal arithmetic, analyze each statement with basic mathematic principles in mind. E.g. two variables require two equations to solve.

For more about the general structure of the GMAT quantitative section check out our GMAT Quant 101.