X^3 . y^2. z >0 => this product is +ve. As y^2 will always +ve, for making full term +ve there are 2 ways..
1) X^3 and z both are +ve => X>0 abd z>0
2) both are -ve => X<0 and z<0.
now
(1) XZ<0 = either X or y is -ve. irrispective of value of y this statment nagate the statement in question. SUFF.
(2)alone y>0 is not helping us as this is anyways not affecting the sigh of over all term as y^2 will be +ve for any value of y. NOT SUFF
Ans : A
Power
This topic has expert replies
Source: Beat The GMAT — Data Sufficiency |
-
cramya
- Legendary Member
- Posts: 2467
- Joined: Thu Aug 28, 2008 6:14 pm
- Thanked: 331 times
- Followed by:11 members
Cartera,
Please use parenetheses if possible.
Its very easy to read the question as x^3y^2z
as x raised to power 3y again raised to power 2z. The question then becomes a little interesting.
Is the question x^3 * y^2 * z like Welcome has solved?
Regards,
CR
Please use parenetheses if possible.
Its very easy to read the question as x^3y^2z
as x raised to power 3y again raised to power 2z. The question then becomes a little interesting.
Is the question x^3 * y^2 * z like Welcome has solved?
Regards,
CR
This can be written as
(x^2)(y^2)(xz)
The (x^2)(y^2) will be positive in all cases except if x or y is 0.
If both 1 and 2 are considered as correct, this means, neither x nor y is 0.
I will go with - Both togther are sufficient.
(x^2)(y^2)(xz)
The (x^2)(y^2) will be positive in all cases except if x or y is 0.
If both 1 and 2 are considered as correct, this means, neither x nor y is 0.
I will go with - Both togther are sufficient.
