gmatbusters wrote:
Given x = y + z. Is x > y ?
1) y > 0
2) z > 0
Great question!
Given: Given x = y + zTarget question: Is x > y ? This is a good candidate for
rephrasing the target question.
Aside: the video below has tips on rephrasing the target questionTake
x > y, and subtract y from both sides to get:
x - y > 0 So, asking
Is x > y? is the SAME AS asking
Is x - y > 0? REPHRASED target question: Is x - y >? Statement 1: y > 0 There are several values of x, y and z that satisfy statement 1. Here are two:
Case a: x = 3, y = 2 and z = 1 (this satisfies the given condition that x = y + z. In this case, x - y = 3 - 2 = 1. So, the answer to the REPHRASED target question is
YES, x - y IS greater than 0Case b: x = 2, y = 3 and z = -1 (this satisfies the given condition that x = y + z. In this case, x - y = 2 - 3 = -1. So, the answer to the REPHRASED target question is
NO, x - y is NOT greater than 0Since we cannot answer the
REPHRASED target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: z > 0It's given that x = y + z
This means that x - y = z
Since statement 1 tells us that z > 0, then it is the case that
x - y > 0PERFECT!!
The answer to the REPHRASED target question is
YES, x - y IS greater than 0Since we can answer the
REPHRASED target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
RELATED VIDEO
_________________
Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
Many students fail to maximize their quant score NOT because they lack the skills to solve certain questions but because they don’t understand what the GMAT is truly testing -
Learn more