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XYZ>0, IS X>0?

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XYZ>0, IS X>0?

by ebehboud » Sat May 02, 2009 11:40 am
XYZ> 0, is X>0?

1) XY>0
2) XZ>0


My reasoning is:
1) Either x,y >0, OR x,y<0 , and no information on Z. insufficient
2) either x,z>0, OR x,z<0, no information on Y. In sufficient.

Together: If X,Y, Z have to be >0 such that XYZ>0 therefor (C)

I don't have the OA.


Thanks ya'll
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Source: — Data Sufficiency |
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by mixpanda » Sat May 02, 2009 1:43 pm
IMO the answer is C.

Neither statement is sufficient alone, but together you see that all three variables must be either negative or positive. Based on the initial assumption that XYZ is greater than zero, negative is ruled out. All variables are positive, so X is greater than 0.
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by ebehboud » Sat May 02, 2009 4:41 pm
Thank you.
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by danimmm » Sun May 03, 2009 11:02 am
xz>0
so...
{X>0 and Z>0} or {X<0 and Z<0}

xy>0
so...
{X>0 and Y>0} or {X<0 and Y<0}

any way x,y and z must all have the same sign.
XYZ>0 => all positive.

X positive and u needed both ...
Answer- C
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Re: XYZ>0, IS X>0?

by chetanojha » Sun May 03, 2009 11:12 am
Statement1: this stmt show X & Y both have same sign. No information about Z. Insufficient.

Statement 2: proves X&Z both have same sign. No information on Y. INSUFF.

Together, it prove X,Y and Z are all save sign and since XYZ>0 all are +ve. Hence X>0.
ebehboud wrote:XYZ> 0, is X>0?

1) XY>0
2) XZ>0


My reasoning is:
1) Either x,y >0, OR x,y<0 , and no information on Z. insufficient
2) either x,z>0, OR x,z<0, no information on Y. In sufficient.

Together: If X,Y, Z have to be >0 such that XYZ>0 therefor (C)

I don't have the OA.


Thanks ya'll
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