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

Redeem

Inequalities problem from OG 11

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
Legendary Member
Posts: 1404
Joined: Tue May 20, 2008 6:55 pm
Thanked: 18 times
Followed by:2 members

by tanviet » Tue Jan 26, 2010 6:15 am
if x<0, x/x/=x.(-x)= -x^2

-x^2<2x

0<2x+x^2

0<x(2+x)

if -2<x<0, the right <0, if x<-2, the right >0, not sufficient

x=-10, sufficient

answer is B
Top
GMAT Instructor
Posts: 1578
Joined: Thu May 28, 2009 8:02 am
Thanked: 128 times
Followed by:34 members
GMAT Score:760

by Osirus@VeritasPrep » Tue Jan 26, 2010 6:16 am
Yeah, that's what I got as well, but the Official Guide says the answer is D. I don't get how A is sufficient, unless there is a typo.
Top
Master | Next Rank: 500 Posts
Posts: 379
Joined: Wed Jun 03, 2009 3:05 am
Thanked: 19 times
Followed by:1 members
GMAT Score:690

by sreak1089 » Tue Jan 26, 2010 6:22 am
I too got B. What is the question number in OG 11?
osirus0830 wrote:Yeah, that's what I got as well, but the Official Guide says the answer is D. I don't get how A is sufficient, unless there is a typo.
Top
GMAT Instructor
Posts: 1578
Joined: Thu May 28, 2009 8:02 am
Thanked: 128 times
Followed by:34 members
GMAT Score:760

by Osirus@VeritasPrep » Tue Jan 26, 2010 6:23 am
sreak1089 wrote:I too got B. What is the question number in OG 11?
osirus0830 wrote:Yeah, that's what I got as well, but the Official Guide says the answer is D. I don't get how A is sufficient, unless there is a typo.
128 in the DS section.

The answer explanation talks about raising x to a power, which leads me to believe there is a typo in the prompt.
Top
Master | Next Rank: 500 Posts
Posts: 379
Joined: Wed Jun 03, 2009 3:05 am
Thanked: 19 times
Followed by:1 members
GMAT Score:690

by sreak1089 » Tue Jan 26, 2010 6:31 am
In my book, it is 2^x, so it must have been a typo in your book. If it is 2^x, then sure it makes sense coz, x * |x| is -ve when x is -ve or equal to -10 and 2^x is always positive.
Top
GMAT Instructor
Posts: 1578
Joined: Thu May 28, 2009 8:02 am
Thanked: 128 times
Followed by:34 members
GMAT Score:760

by Osirus@VeritasPrep » Tue Jan 26, 2010 6:32 am
sreak1089 wrote:In my book, it is 2^x, so it must have been a typo in your book. If it is 2^x, then sure it makes sense coz, x * |x| is -ve when x is -ve or equal to -10 and 2^x is always positive.
Ah, ok, thanks a lot. I thought I was crazy for a minute and with the test in 3 days I was getting nervous...lol
Top
Master | Next Rank: 500 Posts
Posts: 379
Joined: Wed Jun 03, 2009 3:05 am
Thanked: 19 times
Followed by:1 members
GMAT Score:690

by sreak1089 » Tue Jan 26, 2010 6:40 am
No need to worry, you have got it covered :)
osirus0830 wrote:
sreak1089 wrote:In my book, it is 2^x, so it must have been a typo in your book. If it is 2^x, then sure it makes sense coz, x * |x| is -ve when x is -ve or equal to -10 and 2^x is always positive.
Ah, ok, thanks a lot. I thought I was crazy for a minute and with the test in 3 days I was getting nervous...lol
Top
Post new topic Post Reply
• Page 1 of 1