+?-maze

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+?-maze

by sanju09 » Tue Apr 13, 2010 1:54 am
Is x > 0?

(1) x^2 y < 0.

(2) x y > 0.
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by liferocks » Tue Apr 13, 2010 2:02 am
from 1 x^2y<0 since square of real number will be positive,x^2 is positive hence Y<0-->cannot conclude anything about X

from 2 xy> ..tjis is possible if either X or y both are positive or both are -ve-->cannot conclude

combining 1 and 2-> X <0
hence ans C

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by eaakbari » Tue Apr 13, 2010 2:02 am
sanju09 wrote:Is x > 0?

(1) x^2 y < 0.

(2) x y > 0.

Statement one

x^2y < 0
Does not tell us anything about x , though we can conclude y <0

Insuff

Statement two
xy>0
Since we dont know anything about y , we cannot say maybe x and y are both negative or maybe both positive.
Hence Insuff

Combining

From 1 we know y<0
ans since xy>0
then x<0

Therefore Suff

Answer C
Whether you think you can or can't, you're right.
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by outreach » Tue Apr 13, 2010 2:40 am
sanju09 wrote:Is x > 0?

(1) x^2 y < 0.

(2) x y > 0.
1. x can be +ve/-ve. y must be -ve
insuff

2. 2 situations possible
x=+ve y =+ve
x=-ve y =-ve
insuff

combininig
x=-ve y =-ve

hence C
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