x, y and z are real numbers, is xy>0?
x, y and z are real numbers, is xy>0?
(1) xz>0
(2) zy>0
I answered E because x,y,z all three can be -ve in which case answer will be -ve i.e < 0 but the CV Quant test says right answer is C
Hi Sabicha,
Yes x,y,z all could be negative.
But in that case, still x * y is positive .
Question is about product of two numbers x and y, not all three.
So the answer is C.
xz>0 –> not enough information on y so A is not the right option
yz> 0 –> not enough information on x so B is not the right option
and also D goes down with this.
now multiply these two. statement , Remember + * + = +
So zx * yz >0
=> xy* z^2 >0
as z^2 is always >0 So we can remove it.
So we have xy >0 which is enough to answer question Is xy>0 ? answer is yes
This make C as correct
( BTW if z= 0 none of the above statement hold true so we have to consider z as non zero.)
