Data Insights: Data Sufficiency Flashcards

In a Data Sufficiency problem, what does answer choice C indicate?

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.

Is x > 0? (1) x^2 = 9 (2) x^3 = 27

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.

What is the value of integer n? (1) n is a prime number less than 5 (2) n is even

Answer: Both together but neither alone

Primes under 5 are 2 and 3; only 2 is even, so combining the statements gives n=2.

Is the integer k divisible by 6? (1) k is divisible by 3 (2) k is divisible by 4

Answer: Both together but neither alone

Divisibility by 3 and by 4 forces divisibility by 12, which guarantees divisibility by 6.

A common error in Data Sufficiency is to do what?

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.

Is x = 5? (1) x is a solution to x^2 - 10x + 25 = 0 (2) x > 0

Answer: Statement (1) alone is sufficient

The equation factors to (x-5)^2=0, so x=5 uniquely, making (1) alone sufficient.

When testing a 'yes/no' Data Sufficiency question, a statement is sufficient if it yields what?

Answer: A definite yes or a definite no every time

Sufficiency requires a consistent answer; mixed yes/no results make it insufficient.