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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

OG 11 DATA SUFFICIENCY QNO 145

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Sat Oct 11, 2008 5:25 am
Location: INDIA
by georgy » Wed May 13, 2009 4:22 am
GMATONIANS,

PL HELP

IS 1/P > R/(R^2+2) ?

(1) P = R
(2) R > 0

ANS IS C.
I UNDERSTOOD HOW OG 11 ARRIVED AT THIS,BUT I DONT UNDERSTAND WHY MY METHOD IS WRONG, WHICH IS

SUBSTITUTING (1),
1/R > R / (R^2 + 2)
CROSS MULTIPLYING
1>R^2/(R^2 +2)
OR
(R^2 +2)/R^2 > 1
WHICH IS TRUE FOR ALL CASES OF R, + OR - , HENCE ANS IS A

WELL,WHY NOT?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 682
Joined: Fri Jan 16, 2009 2:40 amFollowed by: 1 member
Thanked: 32 times

Re: OG 11 DATA SUFFICIENCY QNO 145

by Vemuri » Wed May 13, 2009 4:37 am
Because you did not consider the negative value of R. What if R<0, then the inequality will be:

R^2/(R^2+2)>1, which cannot be correct because (R^2+2) > R^2.

We need the second statement as well to answer the question.

Hope that helps.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2623
Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members
Location: Montreal
Thanked: 1090 times
GMAT Score:780

Re: OG 11 DATA SUFFICIENCY QNO 145

by Ian Stewart » Wed May 13, 2009 12:45 pm
georgy wrote:
SUBSTITUTING (1),
1/R > R / (R^2 + 2)
CROSS MULTIPLYING
1>R^2/(R^2 +2)
Ron just discussed this in another thread, but you can't 'cross-multiply' with inequalities unless you know whether your denominators are positive or negative. When you 'cross-multiply', you're really multiplying on both sides by both denominators. So in the above, when you cross-multiplied, you were multiplying on both sides by r^2 + 2, and by r. Well, r^2 + 2 is certainly positive, so no problem there, but r could be positive or could be negative. If r is negative, you'd need to reverse the inequality when you multiply by r on both sides. That's why you need the second statement, which guarantees that r is positive, and that you can multiply by r on both sides without needing to worry about reversing the inequality.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Sat Oct 11, 2008 5:25 am
Location: INDIA

OG 11 DS 145

by georgy » Mon May 18, 2009 5:04 am
I SEE,LEARNED SOMETHING NEW TODAY... THANK YOU
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 amFollowed by: 1 member
Thanked: 55 times

by iamcste » Tue May 19, 2009 11:22 am
Using stament 1, can this be simplified to


2/R>0

or have I over simplified it :D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2623
Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members
Location: Montreal
Thanked: 1090 times
GMAT Score:780

by Ian Stewart » Tue May 19, 2009 3:56 pm
iamcste wrote:Using stament 1, can this be simplified to


2/R>0

or have I over simplified it :D
Yes, that's perfect - you can even go further than that.

In detail, when we use Statement 1, we can rephrase the question, by rewriting it algebraically. Note that all we're doing is restating the question in different ways; what we're hoping to find is either:

-something we know to be true, like 2 > 0. Then we'll know we have sufficient information;
-something we don't know is true, like r > 0. Then we'll know we don't have sufficient information, and we'll know exactly what information we need.

Is 1/p > r/(r^2 + 2) ?

Using S1, this becomes:

Is 1/r > r/(r^2 + 2) ?

We can multiply by r^2 + 2, since we know that r^2 + 2 must be positive:

Is (r^2 + 2)/r > r ?
Is (r^2/r) + (2/r) > r ?
Is r + (2/r) > r ?
Is 2/r > 0 ?
Is r > 0?

And now we see why we need Statement 2 as well.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 amFollowed by: 1 member
Thanked: 55 times

by iamcste » Wed May 20, 2009 9:45 am
Ian Stewart wrote:
iamcste wrote:Using stament 1, can this be simplified to


2/R>0

or have I over simplified it :D
Yes, that's perfect - you can even go further than that.

In detail, when we use Statement 1, we can rephrase the question, by rewriting it algebraically. Note that all we're doing is restating the question in different ways; what we're hoping to find is either:

-something we know to be true, like 2 > 0. Then we'll know we have sufficient information;
-something we don't know is true, like r > 0. Then we'll know we don't have sufficient information, and we'll know exactly what information we need.

Is 1/p > r/(r^2 + 2) ?

Using S1, this becomes:

Is 1/r > r/(r^2 + 2) ?

We can multiply by r^2 + 2, since we know that r^2 + 2 must be positive:

Is (r^2 + 2)/r > r ?
Is (r^2/r) + (2/r) > r ?
Is r + (2/r) > r ?
Is 2/r > 0 ?
Is r > 0?

And now we see why we need Statement 2 as well.
Thanks Ian!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1