Data sufficiency questions are part of the GMAT quantitative section of the GMAT. They are a specific type of problem invented explicitly for use in the GMAT.

Question Format

All GMAT data sufficiency questions are in the same format:

1. Question
2. Two Statements
3. Five multiple choice answers

The multiple choice answers are always the same:

• (A) If statement 1 alone is sufficient to answer the question, but statement 2 alone is not sufficient.
• (B) If statement 2 alone is sufficient to answer the question, but statement 1 alone is not sufficient.
• (C) If both statements together are needed to answer the question, but neither statement alone is sufficient.
• (D) If either statement by itself is sufficient to answer the question.
• (E) If not enough facts are given to answer the question.

Data Sufficiency Example

Question: What is ?

1. 
2. 

Answer choices are same as above, as for all data sufficiency questions.

Explanation: Well, statement 1 can’t help you figure anything out on its own, since it’s an equation with 2 variables. Statement 2 can’t help much either – there’s no y in there. So we cancel out options A, B and D. Now think – can we use the two together to find y? Yeah, we can. From 2 we can find x, and plug it into 1 to get y. So the answer is C.

GMAT Data Sufficiency Practice Tests

The only way to improve is practice. Lots of practice. Here’s some practice tests:

GMAT Data Sufficiency (10 practice problems), GMAT Data Sufficiency Problems (30 practice problems), GMAT Data Sufficiency Sample Problems (40 practice problems), GMAT Data Sufficiency Practice (20 practice problems), GMAT Data Sufficiency Questions (25 practice problems), Data Sufficiency Problems GMAT (5 practice problems), GMAT Data Sufficiency Test (20 practice problems), GMAT Data Sufficiency Sample Questions (15 practice problems), Easy GMAT Data Sufficiency (5 practice problems)

Other GMAT Quantitative Question Types

The quantitative section of the GMAT also includes Problem Solving questions.