GMAT Data Sufficiency
Author: Brian Galvin
Size of File: 14 MB
Number Of Pages: 266
Language: English
Category : GMAT
Page Quality: Good
Contents
GMAT Data Sufficiency (DS) Overview
Data Sufficiency is a unique question type in the GMAT Quantitative section designed to test your ability to analyze information and determine whether given data is sufficient to answer a question. Instead of solving for an exact answer, you assess whether the provided statements are enough to find a solution.
GMAT Data Sufficiency Question Format
Each question consists of:
- A question stem (the problem to be solved).
- Two statements labeled (1) and (2), providing additional information.
- Five answer choices, always the same:
Answer Choice | Meaning |
---|---|
A | Statement (1) alone is sufficient, but (2) is not. |
B | Statement (2) alone is sufficient, but (1) is not. |
C | Both statements together are sufficient, but neither alone is. |
D | Each statement alone is sufficient. |
E | Even both statements together are not sufficient to answer the question. |
GMAT Data Sufficiency Strategy
-
Understand the Question Type
- Is it a yes/no question? (e.g., "Is x positive?")
- Is it a value-based question? (e.g., "What is the value of x?")
-
Evaluate Statement (1) Alone
- Determine if it is enough to answer the question.
- If sufficient, eliminate B, C, and E.
-
Evaluate Statement (2) Alone
- If sufficient alone, eliminate A and C.
-
Combine the Statements (if necessary)
- If neither alone is sufficient, check if together they answer the question.
Example GMAT Data Sufficiency Question
Question: What is the value of xxx?
(1) x2=16x^2 = 16x2=16
(2) ∣x∣=4|x| = 4∣x∣=4
Step-by-step Solution
-
Statement (1) Alone: x2=16x^2 = 16x2=16
- Possible values: x=4x = 4x=4 or x=−4x = -4x=−4.
- Since there are two possible values, NOT sufficient. → Eliminate A and D.
-
Statement (2) Alone: ∣x∣=4|x| = 4∣x∣=4
- Possible values: x=4x = 4x=4 or x=−4x = -4x=−4.
- Again, not a unique value → NOT sufficient. → Eliminate B.
-
Combining Both Statements:
- Both give the same information: xxx is either 444 or −4-4−4.
- Still not a single unique value.
- Insufficient.
Final Answer: E (Even both statements together are not sufficient).
GMAT Data Sufficiency Tips
✅ Don’t solve completely—just determine sufficiency.
✅ Check for hidden constraints in absolute values, inequalities, and number properties.
✅ Memorize answer choices to save time.
✅ Watch for Yes/No traps—getting both “yes” and “no” means insufficient.
✅ Think algebraically and conceptually instead of plugging in numbers.
Would you like more practice questions or a focus on specific GMAT DS topics?