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

Redeem

Is x<y?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

Is x<y?

by Max@Math Revolution » Sun Oct 02, 2016 2:46 am
Is x<y?
1) x-y<-4
2) -2x>-2y
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon Oct 03, 2016 10:07 am
Max@Math Revolution wrote:Is x < y?

1) x - y < -4
2) -2x > -2y
Nice question.

Target question: Is x < y?

Statement 1: x - y < -4
Add y to both sides to get: x < y - 4
IMPORTANT: we know that y - 4 < y
So, we can combine y - 4 < y with x < y - 4 to get: x < y - 4 < y
From this we can conclude that x < y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: -2x > -2y
Divide both sides of the inequality by -2 to get: x < y [aside: when we divide both sides of an inequality by a negative value, we must switch the direction of the inequality]
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer = D

RELATED VIDEOS
- Inequalities - Part I: https://www.gmatprepnow.com/module/gmat ... /video/979
- Inequalities - Part II: https://www.gmatprepnow.com/module/gmat ... /video/982
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

by Max@Math Revolution » Tue Oct 04, 2016 6:21 am
==> In the original condition, there are 2 variables, so C is likely to be the answer. As 1)=2), and in the case of 1), from x-y<-4<0, you get x-y<0, x<y, hence yes. The answer is D.
Answer: D
Top
Post new topic Post Reply
• Page 1 of 1