Is n equal to zero?

AbeNeedsAnswers wrote:Is n equal to zero?

(1) The product of n and some nonzero number is 0.
(2) The sum of n and 0 is 0.

D

Source: Official Guide 2020

Target question: Is n equal to zero?

Statement 1: The product of n and some nonzero number is 0
(n)(non-zero number) = 0
This means n must be 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: The sum of n and 0 is 0
If n + 0 = 0, we can conclude that n must be 0
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent

Hi All,

We're asked if N is equal to zero. This is a YES/NO question and can be answered with a mix of Number Properties and TESTing VALUES.

(1) The PRODUCT of N and some NON-ZERO number is 0

When multiplying any non-zero number by 0, the result will ALWAYS be 0 (for example: 1x0 = 0, 27x0 = 0, 0x135 = 0, etc.). With the information in Fact 1, we're multiplying two numbers - one of which we know is a non-zero number. Thus, the other number (re: "N") MUST be equal to zero, so the answer to the question is ALWAYS YES.
Fact 1 is SUFFICIENT

(2) The SUM of N and 0 is 0.

When adding two numbers together, there are two ways to end up with a sum of 0. The first is if the numbers are 'opposites' (for example: 1 and -1, 2 and -2, -17 and 17, etc.), then the sum will be zero. The second is if both numbers equal 0. The information in Fact 2 describes the second, so N MUST be 0 and the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT

Final Answer: D

GMAT assassins aren't born, they're made,
Rich