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 : Is xy > 0?

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 176
Joined: Sun Feb 21, 2010 6:00 am
Thanked: 2 times
GMAT Score:710
by Pdgmat2010 » Fri May 28, 2010 4:18 am
Is xy > 0?

1. x - y > -2
2. x - 2y < -6


okay, my understanding is, if its not specified whether x and y are equal to zero, we can consider them or one of them as zero. ( pls dont SC my previous sentence.. its totally crazy i know.. LOLZ!!)

but the answer is
C

can someone share some insight?

Cheers,
Pd
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Legendary Member
Posts: 576
Joined: Sat Mar 13, 2010 8:31 pmFollowed by: 1 member
Thanked: 97 times

by liferocks » Fri May 28, 2010 4:28 am
if xy > 0 both x and y has to have same sign,clearly from either statements we cannot conclude this.
combining
x>y-2 and x<2y-6

so 2y-6>y-2
or y>4..so y is positive

x>4-2 or x>2..hence x is also positive..so xy>0..sufficient

Ans option C
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2326
Joined: Mon Jul 28, 2008 3:54 amFollowed by: 2 members
Thanked: 173 times
GMAT Score:710

by gmatmachoman » Fri May 28, 2010 4:33 am
liferocks wrote:if xy > 0 both x and y has to have same sign,clearly from either statements we cannot conclude this.
combining
x>y-2 and x<2y-6

so 2y-6>y-2
or y>4..so y is positive

x>4-2 or x>2..hence x is also positive..so xy>0..sufficient

Ans option C
LR how did u decide X>4-2???
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 176
Joined: Sun Feb 21, 2010 6:00 am
Thanked: 2 times
GMAT Score:710

by Pdgmat2010 » Fri May 28, 2010 4:35 am
since y > 4
he substituted the value of y in the inequality x > y - 2
x > 4 - 2
x > 2
hence C
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 1052
Joined: Fri May 21, 2010 1:30 amFollowed by: 98 members
Thanked: 335 times

by Patrick_GMATFix » Fri May 28, 2010 9:35 am
Liferock's explanation is great.

An alternative in merging statements is to do the following:

(1) x-y > -2
(2) x-2y < -6

Multiply (1) by -2 to get -2x+2y < 4. Add this to (2) and you'll end up with -x<-2 --> x>2
Multiply (2) by -1 to get -x+2y > 6. Add this to (1) and you'll end up with y>4

So x>2 and y>4. We have enough data to know that xy>0. The answer is C

A video solution is available at GMATPrep question 1125

Good luck,
-Patrick
  • Ask me about tutoring.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1