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Source: — Data Sufficiency |
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by user123321 » Thu Jan 12, 2012 7:54 am
sud21 wrote:uv>0,is (u^2)(v^3)>0?
1). u>0
2). v<0
1) u>0
given uv>0 => either U,V both greater than 0 or both less than 0.
since U >0 , we have V >0. hence u^2.v^3 > 0. hence suff.

2) v<0
since v<0, u<0, hence u^2.v^3<0 for sure. hence suff.

[spoiler]IMO D?[/spoiler]

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by ArunangsuSahu » Thu Jan 12, 2012 8:07 am
This will always depend on the sign of v

Statement 1: SUFFICIENT
Statement 2: SUFFICIENT

(D) is the answer
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by sam2304 » Thu Jan 12, 2012 8:16 am
How can this be possible ? A DS question will have only one answer. For this sort a YES or a NO

With 1 we get a YES
With 2 we get a NO

Both are contradicting each other. It shouldn't be the case. Is the question right ? ?
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by neelgandham » Thu Jan 12, 2012 8:25 am
I agree with Sam2304.

sud21

Can you please post the source of the question and the OA as well please ?
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by sud21 » Fri Jan 13, 2012 9:02 am
sam2304 wrote:How can this be possible ? A DS question will have only one answer. For this sort a YES or a NO

With 1 we get a YES
With 2 we get a NO

Both are contradicting each other. It shouldn't be the case. Is the question right ? ?
In this situation where two statements are seemed to contradict each other, we have to see the question first, that is, whose value between u and v is important in order to find out the answer.

Here, since uv>0, we can find that both u and v are either positive or negative. So, we are concerned with the value of v because u^2 will always be positive.

So St.1 although looks sufficient will not be the conclusive answer.

Therefore St.2 will give the answer which states that v<0, so we find out that the expression u^2v^3 is less than 0.

So the answer is B.
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by Brent@GMATPrepNow » Fri Jan 13, 2012 9:36 am
sam2304 wrote:How can this be possible ? A DS question will have only one answer. For this sort a YES or a NO

With 1 we get a YES
With 2 we get a NO

Both are contradicting each other. It shouldn't be the case. Is the question right ? ?
Good observation, sam2304,

The two statements in a DS question will never contradict each other.

Statement 1 essentially says that u and v MUST be both positive.
Statement 2 essentially says that u and v MUST be both negative.
So, this could never be an official GMAT question, since the two statements contradict each other.

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