Data Sufficiency

Gmat_mission wrote:Does x + c = y + c ?

(1) x = y
(2) x = c

Target question: Does x + c = y + c ?
This is a good candidate for rephrasing the target question.
Take the equation x + c = y + c, and subtract c from both sides to get: x = y

REPHRASED target question: Does x = y ?

Aside: Here's a video with tips on rephrasing the target question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1100

Statement 1: x = y
Perfect!The answer to the REPHRASED target question is YES, x = y
Since we can answer the REPHRASED target question with certainty, statement 1 is SUFFICIENT

Statement 2: x = c
Since we know nothing about the value of y, we cannot answer the REPHRASED target question
Statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent