Is x+y > 0?

[M7MBA]

Is x+y > 0?

(1) x > y
(2) x + y -1 >0

The OA is the option B.

Why is not sufficient the first statement? Also, why is sufficient the second one? I need a clarification here. Thanks in advance.

[Vincen]

Is x+y > 0?

(1) x > y
(2) x + y -1 >0

The OA is the option B.

Why is not sufficient the first statement? Also, why is sufficient the second one? I need a clarification here. Thanks in advance.

Hi M7MBA.

Let's take a look at your question.

First statement

(1) x > y

Here, we can have the following cases:

- x=1 and y=0, then x+y=1 > 0. YES

- x=1 and y=-5, then x+y=-4 < 0. NO

Hence, this statement is NOT SUFFICIENT.

Second statement

(2) x + y -1 >0

Here, if we solve for x and y we get: $$x+y-1>0\ \ \ \Rightarrow\ \ \ x+y>1>0.\ \ \ \ \ YES.$$ Therefore, this statement is SUFFICIENT.

In conclusion, the correct answer is the option B.

I hope it helps.

[Brent@GMATPrepNow]

Is x+y > 0?

(1) x > y
(2) x + y -1 > 0

Target question: Is x+y > 0?

Statement 1: x > y
Let's TEST some values.
There are several values of x and y that satisfy statement 1. Here are two:
Case a: x = 2 and y = 1 (this satisfies the condition that x > y). In this case, x + y = 2 + 1 = 3. So, the answer to the target question is YES, x+y IS greater than 0
Case b: x = 0 and y = -1 (this satisfies the condition that x > y). In this case, x + y = 0 + (-1) = -1. So, the answer to the target question is NO, x+y is NOT greater than 0
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: x + y -1 > 0
First recognize that x + y > x + y - 1, we can now say: x + y > x + y - 1 > 0
Now, if we ignore the x + y - 1 part, we can see that x + y > 0
So, the answer to the target question is YES, x+y IS greater than 0
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent

[Jeff@TargetTestPrep]

Is x+y > 0?

(1) x > y
(2) x + y -1 >0

Statement One Alone:

x > y

Statement one alone is not sufficient to answer the question. For example, if x = 2 and y = 1, then x + y > 0. However, if x = -1 and y = -2, then x + y is not greater than 0.

Statement Two Alone:

x + y - 1 > 0

We see that x + y > 1. If x + y > 1, then x + y > 0. Statement two alone is sufficient to answer the question.

Answer: B