Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
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.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
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 Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart 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 563 reviewsTarget Test Prep

DS Question??

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Sun Jan 06, 2008 7:58 pm
by rganesh » Wed Apr 09, 2008 1:56 pm
I'm stuck wondering why the answer is B and not D. Can someone explain why?
Is x2 equal to xy?
(1) x2 – y2 = (x + 5)(y - 5)
(2) x = y

I undersand the 2nd statement however, won't the answer to statement 1 be NO x2 does not equal xy and therefore it is sufficent because we are able to answer the Yes or No question?

I appreciate you assistance, maybe I am complicating things....
Top
Join the discussion
Source: — Data Sufficiency |
Legendary Member
Posts: 519
Joined: Sat Jan 27, 2007 7:56 am
Location: India
Thanked: 31 times

by Neo2000 » Wed Apr 09, 2008 9:55 pm
Umm how are you getting No from 1??

1 Equation , 2 unknowns => Cannot be solved. Nothing can be said from 1.

Atleast, i reasoned it that way. Am i missing something?
Top
Join the discussion
User avatar
GMAT Instructor
Posts: 3224
Joined: Tue Jan 08, 2008 2:40 pmFollowed by: 614 members
Location: Toronto
Thanked: 1710 times
GMAT Score:800

Re: DS Question??

by Stuart@KaplanGMAT » Thu Apr 10, 2008 10:59 am
rganesh wrote:I'm stuck wondering why the answer is B and not D. Can someone explain why?
Is x2 equal to xy?
(1) x2 – y2 = (x + 5)(y - 5)
(2) x = y

I undersand the 2nd statement however, won't the answer to statement 1 be NO x2 does not equal xy and therefore it is sufficent because we are able to answer the Yes or No question?

I appreciate you assistance, maybe I am complicating things....
We can rewrite statement (1) as:

(x+y)(x-y) = (x+5)(y-5)

We're allowed to pick x=5 and y=5 (since (10)(0) = (10)(0)).
Is 5^2 = 5*5? YES.

We're also allowed to pick x=-5 and y=5 (since (0)(-10) = (0)(0)).
Is (-5)^2 = 5*(-5)? NO.

We can get both a "yes" and a "no", so (1) is insufficient.
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Sun Jan 06, 2008 7:58 pm

Thanks!

by rganesh » Fri Apr 11, 2008 8:26 am
That's exactly the explanation I was looking for!
Much appreciated.
R
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 27
Joined: Thu Apr 10, 2008 1:20 pm
Thanked: 1 times

by humeixia » Fri Apr 11, 2008 3:53 pm
Yes, the answer is A.
Top
Join the discussion