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by Brent@GMATPrepNow » Mon Feb 27, 2012 10:23 am
anandhimanshu85 wrote:If x > 0 , is yx > x ?
(1) 0 < y < 1
(2) x > 1

OA: I answered it as D but the OA is given as A.Can anyone explain?
This one's a great candidate for rephrasing the target question.

Since we are told that x is positive, we can take our original target questions (Is yx > x ?) and divide both sides by x to get the rephrased target question: Is y > 1?
Now let's check the statements.

Statement 1: 0 < y < 1
From this information, we can be certain that y is not greater than 1.
So, statement 1 is SUFFICIENT

Statement 2: x > 1
From this information, we have no idea about whether y is greater than 1.
So, statement 2 is INSUFFICIENT

The answer is A

Cheers,
Brent
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by Mike@Magoosh » Mon Feb 27, 2012 10:28 am
Hi, there. I'm happy to help with this.

Prompt:
If x > 0 , is yx > x?

We are told that x is a positive number, greater than zero, so in the inequality yx > x, we can divide both sides by x. That leaves us with y > 1. So, the question "yx > x?" is entirely equivalent to the question "y > 1?"

Statement #1: 0 < y < 1
This indeed tells us that y is not greater than one. We can give a definitive "no" answer to the prompt. Because we can give a definitive answer, this means we have sufficient information. Statement #1, by itself, is sufficient.

Statement #2: x > 1
Well, we already knew that x was greater than zero. This doesn't change much, and it doesn't give any new information about whether y is greater than 1 or not. Statement #2, by itself, is insufficient.

Answer = A

Does that make sense?

Mike :)
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by anandhimanshu85 » Mon Feb 27, 2012 10:28 am
Hello Brent,

I am sorry, actually the question stem was not correct, can you please tak a look as I have modified the question stem...sorry for the inconvenience.

Thanks,
Himanshu
Last edited by anandhimanshu85 on Mon Feb 27, 2012 10:35 am, edited 1 time in total.
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by anandhimanshu85 » Mon Feb 27, 2012 10:34 am
Hello Mike,

I am sorry, actually the question stem was not correct, can you please tak a look as I have modified the question stem...sorry for the inconvenience.

Thanks,
Himanshu
Mike@Magoosh wrote:Hi, there. I'm happy to help with this.

Prompt:
If x > 0 , is yx > x?

We are told that x is a positive number, greater than zero, so in the inequality yx > x, we can divide both sides by x. That leaves us with y > 1. So, the question "yx > x?" is entirely equivalent to the question "y > 1?"

Statement #1: 0 < y < 1
This indeed tells us that y is not greater than one. We can give a definitive "no" answer to the prompt. Because we can give a definitive answer, this means we have sufficient information. Statement #1, by itself, is sufficient.

Statement #2: x > 1
Well, we already knew that x was greater than zero. This doesn't change much, and it doesn't give any new information about whether y is greater than 1 or not. Statement #2, by itself, is insufficient.

Answer = A

Does that make sense?

Mike :)
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by Brent@GMATPrepNow » Mon Feb 27, 2012 10:42 am
anandhimanshu85 wrote:Hello Brent/Mike,

I am sorry, actually the question stem was not correct, can you please tak a look as I have modified the question stem...sorry for the inconvenience.

Thanks,
Himanshu
Hi Himanshu,

The slight change to the original target question doesn't change much.

Since we are told that x is positive, we can take our original target question (Is x/y > x ?) and divide both sides by x to get the rephrased target question: Is 1/y > 1?

Now, under what circumstances is 1/y > 1?
Well, for this to hold true, it must be the case that 0 < y < 1.
In other words the inequality 1/y > 1 is equivalent to the inequality 0 < y < 1.

Given this, we can re-rephrase the target question as (Is 0 < y < 1 ?)

Now let's check the statements.

Statement 1: 0 < y < 1
From this information, we can be certain that 0 < y < 1
So, statement 1 is SUFFICIENT

Statement 2: x > 1
From this information, we have no idea about whether or not 0 < y < 1 .
So, statement 2 is INSUFFICIENT

The answer is A

Cheers,
Brent
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