set 19 Q. 13

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 139
Joined: Sun Nov 09, 2008 12:04 am
Thanked: 3 times
GMAT Score:620

set 19 Q. 13

by Rashmi1804 » Fri Apr 03, 2009 7:26 am
DS

If x and y are positive, is 3x > 7y?
(1) x > y + 4
(2) -5x < -14y

Could anyone explain how is A sufficient ??

OA: D

I guess the OA is wrong!!
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

Re: set 19 Q. 13

by Brent@GMATPrepNow » Fri Apr 03, 2009 9:08 am
Rashmi1804 wrote:DS
If x and y are positive, is 3x > 7y?
(1) x > y + 4
(2) -5x < -14y
Could anyone explain how is A sufficient ??
OA: D
I guess the OA is wrong!!
I don't believe (1) is sufficient
Case a) y=1 and x=6: we get 3(6) > 7(1)
Case b) y=100 and x=105: we get 3(105) < 7(100)
Brent Hanneson - Creator of GMATPrepNow.com
Image

Master | Next Rank: 500 Posts
Posts: 322
Joined: Fri Mar 27, 2009 3:56 pm
Thanked: 24 times
GMAT Score:710

by mike22629 » Fri Apr 03, 2009 9:10 am
I believe you are correct. if you fill in possible values of x and y with the first constraint you can find 3x greater than or less than 7y. When adding or subtracting a value in a ratio, the relationship does not stay constant.

I believe it is B.