GMAT Data Insights: Data Sufficiency 2 — Questions and Answers
Question 1: In a Data Sufficiency problem, what does answer choice C indicate?
- Statement (1) alone is sufficient
- Statement (2) alone is sufficient
- Both statements together are sufficient, but neither alone is sufficient (Correct answer)
- Each statement alone is sufficient
Correct answer: Both statements together are sufficient, but neither alone is sufficient
Choice C means the two statements together suffice, but neither is enough on its own.
Question 2: Is x > 0? (1) x^2 = 9 (2) x^3 = 27
- Statement (1) alone is sufficient
- Statement (2) alone is sufficient (Correct answer)
- Both together but neither alone
- Each alone is sufficient
Correct answer: Statement (2) alone is sufficient
x^2=9 gives x=±3 (insufficient), but x^3=27 gives only x=3, so (2) alone is sufficient.
Question 3: What is the value of integer n? (1) n is a prime number less than 5 (2) n is even
- Statement (1) alone is sufficient
- Statement (2) alone is sufficient
- Both together but neither alone (Correct answer)
- Each alone is sufficient
Correct answer: Both together but neither alone
Primes under 5 are 2 and 3; only 2 is even, so combining the statements gives n=2.
Question 4: Is the integer k divisible by 6? (1) k is divisible by 3 (2) k is divisible by 4
- Statement (1) alone is sufficient
- Statement (2) alone is sufficient
- Both together but neither alone (Correct answer)
- Each alone is sufficient
Correct answer: Both together but neither alone
Divisibility by 3 and by 4 forces divisibility by 12, which guarantees divisibility by 6.
Question 5: A common error in Data Sufficiency is to do what?
- Solve for the exact value when only sufficiency is needed (Correct answer)
- Read both statements
- Consider negative numbers
- Check whether each statement is alone sufficient
Correct answer: Solve for the exact value when only sufficiency is needed
You only need to determine if the answer can be found, not calculate the final number.
Question 6: Is x = 5? (1) x is a solution to x^2 - 10x + 25 = 0 (2) x > 0
- Statement (1) alone is sufficient (Correct answer)
- Statement (2) alone is sufficient
- Both together but neither alone
- Each alone is sufficient
Correct answer: Statement (1) alone is sufficient
The equation factors to (x-5)^2=0, so x=5 uniquely, making (1) alone sufficient.
Question 7: When testing a 'yes/no' Data Sufficiency question, a statement is sufficient if it yields what?
- A definite yes or a definite no every time (Correct answer)
- Sometimes yes and sometimes no
- Only a yes answer
- An exact numeric value
Correct answer: A definite yes or a definite no every time
Sufficiency requires a consistent answer; mixed yes/no results make it insufficient.
GMAT Data Insights: Data Sufficiency 2
In a Data Sufficiency problem, what does answer choice C indicate?