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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

GMAT PREP I Inequality

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 266
Joined: Mon Oct 19, 2009 9:46 pm
Thanked: 8 times
GMAT Score:690
by pkw209 » Tue Jan 05, 2010 10:07 am
Hi everyone,

Had a little trouble with this question. What's the fastest/best approach to solving this? FYI, I took this from Zuleron's list of gmat prep questions. The answer is C. thanks!

110) Is m + z > 0?

a. m - 3z > 0
b. 4z - m > 0
Last edited by pkw209 on Mon Apr 26, 2010 3:18 pm, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Tue Jan 05, 2010 6:51 pm
I discussed this question here:

https://www.beatthegmat.com/is-m-z-0-t48172.html
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pmFollowed by: 252 members
Thanked: 653 times

by papgust » Tue Jan 05, 2010 6:54 pm
pkw209 wrote:Is m + z > 0
a. m - 3z > 0
b. 4z - m > 0
a. m > 3z

If z is +ve, m is also +ve and m+z > 0. YES
If z is -ve, m is also -ve and m+z < 0. NO
Insufficient.

b. 4z > m

Same reasoning as stmt I. Insufficient.

Combined,

3z < M < 4z. In order to form this inequality, z must be greater than 0 (or positive). As M is greater than 3z, M is also positive. So, m+z > 0.
Sufficient.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 266
Joined: Mon Oct 19, 2009 9:46 pm
Thanked: 8 times
GMAT Score:690

by pkw209 » Wed Jan 06, 2010 9:59 am
Thanks guys. Sorry for the slow response, I've been extremely busy.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 266
Joined: Mon Oct 19, 2009 9:46 pm
Thanked: 8 times
GMAT Score:690

by pkw209 » Wed Jan 06, 2010 10:13 am
I got to C or E and my problem was that I subtracted the inequalities rather than add them as Testluv pointed out in his post.

However, I also tried picking numbers and that would satisfy both inequalities and couldn't find a pair that satisfied both. Considering that when you add the inequalities, the result is z>0, does that mean there are no two pairs but just that z is positive?

Also, I'm assuming it's ok if you simplify the question stem to is m>-z?

thanks.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pmFollowed by: 164 members
Location: Toronto
Thanked: 539 times
GMAT Score:800

by Testluv » Wed Jan 06, 2010 12:31 pm
Also, I'm assuming it's ok if you simplify the question stem to is m>-z?
Yes.

Once you combine, you know that z>0. And you know from (1) that m is bigger than z (ie, m>3z). Therefore, both must be positive; therefore, their sum is positive.
Kaplan Teacher in Toronto
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 266
Joined: Mon Oct 19, 2009 9:46 pm
Thanked: 8 times
GMAT Score:690

by pkw209 » Wed Jan 06, 2010 2:07 pm
I just chose two positive numbers, z=2 and m=7 and the inequality worked. Not sure what I'm doing with some of these questions sometimes...

Anyway, thanks Testluv.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1