x^5 y^4 z^2 < 0

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

x^5 y^4 z^2 < 0

by sanju09 » Fri Jul 23, 2010 6:14 am
If x^5 y^4 z^2 < 0, which of the following must be true?
I. x y < 0
II. y z < 0
III. x z < 0
A. I
B. II
C. III
D. I and II
E. None

[spoiler]Source: majortests.com[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

User avatar
Master | Next Rank: 500 Posts
Posts: 233
Joined: Mon Jun 09, 2008 1:30 am
Thanked: 5 times

by blaster » Fri Jul 23, 2010 6:17 am
i think it must be E

User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pm
Thanked: 215 times
Followed by:7 members

by kvcpk » Fri Jul 23, 2010 6:24 am
sanju09 wrote:If x^5 y^4 z^2 < 0, which of the following must be true?
I. x y < 0
II. y z < 0
III. x z < 0
A. I
B. II
C. III
D. I and II
E. None

[spoiler]Source: majortests.com[/spoiler]
y^4 and z^2 cannot be <0

Hence x^5 should be less than 0
which means x<0
We have no info about y and z
Hence pick E