BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

GMAT PREP tougie

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 101
Joined: Thu Jan 06, 2011 12:44 am
Thanked: 1 times

GMAT PREP tougie

by btgyes » Thu Feb 24, 2011 4:22 am
after solving both .

3Z < M < 4Z

now let say M = 3.5 Z,
now putting in main eq ie is M + Z > 0

ie M + 3.5 Z > 0
or 4.5 Z > 0

can't say because Z still can be negative.

So i found and E

but OA is different

plz help..

ta
Attachments
10.JPG
Top
Source: — Data Sufficiency |
Legendary Member
Posts: 1578
Joined: Sun Dec 28, 2008 1:49 am
Thanked: 82 times
Followed by:9 members
GMAT Score:720

by maihuna » Thu Feb 24, 2011 4:30 am
Aha so u donot got the expert only reply so reposting is't.

I think someone/may be u recently posted this Q.

C is a clear ans:

Adding both statements it gives : z>0

1 says : m>3z => m>0

COmbining m>0 as z>0

so m+z>0

It is a clear C, what is the confusion?
Charged up again to beat the beast :)
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Thu Feb 24, 2011 4:48 am
(1) m - 3z > 0 or m > 3z. From here we cannot say whether m + z > 0.
So, (1) is NOT SUFFICIENT.

(2) 4z - m > 0 or 4z > m. Again we cannot say whether m + z > 0.
So, (2) is NOT SUFFICIENT.

Combining (1) and (2), 3z < m < 4z

If z = -1, then the above inequality becomes -3 < m < -4, but that is not true as -3 > -4. Hence z can never be negative as 3z < m < 4z turns false in that case.
This implies z has to be positive and since m lies between 3z and 4z, which are positive so m will also be positive. Hence m + z > 0 is true.

The correct answer is C.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Legendary Member
Posts: 1578
Joined: Sun Dec 28, 2008 1:49 am
Thanked: 82 times
Followed by:9 members
GMAT Score:720

by maihuna » Thu Feb 24, 2011 4:52 am
Anurag,
you can simply add the two stmts that gives z>0

No need to cumbersome arithmetic, preety st forward.
Anurag@Gurome wrote:(1) m - 3z > 0 or m > 3z. From here we cannot say whether m + z > 0.
So, (1) is NOT SUFFICIENT.

(2) 4z - m > 0 or 4z > m. Again we cannot say whether m + z > 0.
So, (2) is NOT SUFFICIENT.

Combining (1) and (2), 3z < m < 4z

If z = -1, then the above inequality becomes -3 < m < -4, but that is not true as -3 > -4. Hence z can never be negative as 3z < m < 4z turns false in that case.
This implies z has to be positive and since m lies between 3z and 4z, which are positive so m will also be positive. Hence m + z > 0 is true.

The correct answer is C.
Charged up again to beat the beast :)
Top
Master | Next Rank: 500 Posts
Posts: 101
Joined: Thu Jan 06, 2011 12:44 am
Thanked: 1 times

by btgyes » Thu Feb 24, 2011 6:00 am
Thanks Guys..

You are brilliant...!
Top
Post new topic Post Reply
• Page 1 of 1