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

Redeem

OG11 DS #142

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 226
Joined: Tue Jan 13, 2009 1:27 pm
Thanked: 23 times
Followed by:1 members

OG11 DS #142

by awesomeusername » Sat Apr 25, 2009 12:00 am
In the question, for (2), it states:

x > 0 = b

I am not familiar with this type of inequality. Does this mean that x>0 and b=0, or x=b?

thx
Constant dripping hollows out a stone.
-Lucretius
Top
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 682
Joined: Fri Jan 16, 2009 2:40 am
Thanked: 32 times
Followed by:1 members

Re: OG11 DS #142

by Vemuri » Sat Apr 25, 2009 4:22 am
awesomeusername wrote:In the question, for (2), it states:

x > 0 = b

I am not familiar with this type of inequality. Does this mean that x>0 and b=0, or x=b?

thx
Please be kind enough to post the question. Not everyone in this forum has the OG.
Top
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Fri Mar 18, 2011 11:34 am

by gpaggie07 » Mon Jul 18, 2011 8:30 pm
Nevermind, found it is a typo here: https://www.beatthegmat.com/exponents-qu ... ent=Boston
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 » Mon Jul 18, 2011 9:35 pm
awesomeusername wrote:In the question, for (2), it states:

x > 0 = b

I am not familiar with this type of inequality. Does this mean that x>0 and b=0, or x=b?

thx
The exact question is as below:

If x is an integer, is 9^x + 9^(-x) = b?
(1) 3^x + 3^(-x) = √(b + 2)
(2) x > 0

Explanation:

(1) Square both sides of 3^x + 3^(-x) = √(b + 2)
3^(2x) + 3^(-2x) + 2[3^x * 3^(-x)] = b + 2
9^x + 9^(-x) + 2[3^(x - x)] = b + 2
9^x + 9^(-x) + 2[3^0] = b + 2
9^x + 9^(-x) + 2 = b + 2 (since 3^0 = 1)
So, 9^x + 9^(-x) = b; SUFFICIENT.

(2) x > 0 does not give us any information about b, so statement 2 is NOT sufficient.

The correct answer is A.
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