Is x-y+1 greater than x+y-1 ?

[BTGmoderatorDC]

Is x-y+1 greater than x+y-1 ?

(1) x > 0
(2) y < 0

OA B

Source: GMAT Prep

[GMATinsight]

Is x-y+1 greater than x+y-1 ?

(1) x > 0
(2) y < 0

OA B

Source: GMAT Prep

Question : Is x-y+1 > x+y-1 ?

Question : Is 2y < 2?

Question : Is y < 1?

Statement 1: x > 0
NOT SUFFICIENT

Statement 2: y < 0

i.e. y is NOT greater than 1 hence

SUFFICIENT

Answer: Option B

[Brent@GMATPrepNow]

Is x-y+1 greater than x+y-1 ?

(1) x > 0
(2) y < 0

Target question: Is x - y + 1 > x + y - 1 ?
This is a good candidate for rephrasing the target question.

Take: x - y + 1 > x + y - 1
Subtract x from both sides to get: -y + 1 > y - 1
Add y to both sides to get: 1 > 2y - 1
Add 1 to both sides to get: 2 > 2y
Divide both sides by 2 to get: 1 > y
REPHRASED target question: Is y < 1?

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

Statement 1: x > 0
Since we have no information about y, we cannot answer the REPHRASED target question with certainty
Statement 1 is NOT SUFFICIENT

Statement 2: y < 0
In other words, y is NEGATIVE
If is NEGATIVE, then y is definitely less than 1
So, the answer to the REPHRASED target question is YES, y IS less than 1
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: B

Cheers,
Brent