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

Redeem

gmat prep 2

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 228
Joined: Sun Aug 17, 2008 8:08 am
Thanked: 4 times

gmat prep 2

by jainrahul1985 » Tue Jul 26, 2011 12:19 am
If -2x > 3y, is x negative?

(1) y > 0
(2) 2x + 5y - 20 = 0

OA D

1)-2x > 3y
=> x < -(3/2)y
Also y > 0

Therefore x has to be negative

Experts please help me understand why Statement 2 is sufficient
Top
Source: — Data Sufficiency |
User avatar
GMAT Instructor
Posts: 905
Joined: Sun Sep 12, 2010 1:38 am
Thanked: 378 times
Followed by:123 members
GMAT Score:760

by Geva@EconomistGMAT » Tue Jul 26, 2011 12:26 am
jainrahul1985 wrote:If -2x > 3y, is x negative?

(1) y > 0
(2) 2x + 5y - 20 = 0

OA D

1)-2x > 3y
=> x < -(3/2)y
Also y > 0

Therefore x has to be negative

Experts please help me understand why Statement 2 is sufficient
Isolate x:

2x=20-5y

Multiply by -1 to get the -2x from the question stem:

-2x=-(20-5y)
-2x = -20+5y
-2x=5y-20.
Now you know that -2x>3y, so you can say that

5y-20>3y
2y>20
y>10

which means that y is positive, same as (1).
Geva
Senior Instructor
Master GMAT
1-888-780-GMAT
https://www.mastergmat.com
Top
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Jul 26, 2011 12:34 am
jainrahul1985 wrote:If -2x > 3y, is x negative?

(1) y > 0
(2) 2x + 5y - 20 = 0

OA D

1)-2x > 3y
=> x < -(3/2)y
Also y > 0

Therefore x has to be negative

Experts please help me understand why Statement 2 is sufficient
Statement 1: y > 0
Since y > 0, 3y > 0.
Linking together -2x > 3y and 3y > 0, we get:
-2x > 3y > 0
-2x > 0
x < 0.
Sufficient.

Statement 2: 2x + 5y - 20 = 0
Thus, 5y-20 = -2x.
Substituting 5y-20 for -2x in -2x > 3y, we get:
5y-20 > 3y
2y > 20
y > 10.
We saw in statement 1 that y > 0 implies that x < 0.
Sufficient.

The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Tue Jul 26, 2011 4:05 am
jainrahul1985 wrote:If -2x > 3y, is x negative?

(1) y > 0
(2) 2x + 5y - 20 = 0

OA D

1)-2x > 3y
=> x < -(3/2)y
Also y > 0

Therefore x has to be negative

Experts please help me understand why Statement 2 is sufficient
Got a PM to reply on this thread.

(1) y > 0 implies 3y > 0, which implies -2x > 0, which means -2x should be a positive value.
For -2x to be positive, x should be a negative value; SUFFICIENT.

(2) 2x + 5y - 20 = 0 or -2x = 5y - 20
Now -2x > 3y implies 5y - 20 > 3y or 2y > 20 or y > 10, which implies y is a positive value. And hence, x should be negative; SUFFICIENT.

The correct answer is D.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Post new topic Post Reply
• Page 1 of 1