Is x a positive number?

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 29
Joined: Mon Mar 09, 2009 6:39 am

Is x a positive number?

by EbrahimHashem » Thu Jul 30, 2009 10:24 am
Is x a positive number?

(1) x + 6>2
(2) X^2 > 25



Have fun :D

User avatar
MBA Admissions Consultant
Posts: 1090
Joined: Wed May 27, 2009 4:06 am
Thanked: 175 times
Followed by:68 members
GMAT Score:750

by Bryant@VeritasPrep » Thu Jul 30, 2009 10:29 am
I would say yes, x is a positive number, as there is not a negative number that will satisfy both equations. OA?
Bryant Michaels
MBA Admissions Consultant


Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options

Master | Next Rank: 500 Posts
Posts: 175
Joined: Mon Feb 09, 2009 3:57 pm
Thanked: 4 times

by tom4lax » Thu Jul 30, 2009 11:21 am
IMO C

Senior | Next Rank: 100 Posts
Posts: 50
Joined: Thu Apr 09, 2009 10:33 am

by gmat_2010 » Thu Jul 30, 2009 1:40 pm
IMO C

x + 6 > 2 implies x > -4
x^2 > 25 implies either x > 5, or x < -5

Hence, x has to be > 5. Hence, x is positive.

Senior | Next Rank: 100 Posts
Posts: 50
Joined: Tue Apr 18, 2006 5:41 pm
Thanked: 2 times
Followed by:1 members

by tngearhart » Thu Jul 30, 2009 2:04 pm
I think the answer is E

If x>-4, x could be either positive or negative, Insufficent

If x>5 or x<-5, x could be either positive or negative, insufficent.

Looking at both together, we cannot tell if x>0 from the three inequalities we have.

Master | Next Rank: 500 Posts
Posts: 186
Joined: Sat Sep 02, 2006 7:50 pm
Thanked: 10 times
Followed by:1 members

by ogbeni » Fri Jul 31, 2009 8:16 am
Answer is C. It has to be C because when you combine both statements you are ask whether: the sign next to numbers, where x>-4 and x^2>25, is positive. The answer has to be where the combined statements are rue. For the both statements to be true, the values of x are, x>6 and for that range we get positive numbers, therefore, C

Legendary Member
Posts: 527
Joined: Thu May 01, 2008 12:06 am
Thanked: 7 times

by real2008 » Fri Jul 31, 2009 8:56 am
answer must be C. OA please?

Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Mon Jul 27, 2009 5:46 pm
Location: LA,CA

I got B as my answer

by mark412 » Mon Aug 17, 2009 5:07 pm
Is x Pos?

1) X+6> 2 therefore, x>-4. Could be either pos or neg.

Insuf.

2) x^2>25 so x^2-25>0 factor down: (x-5)(x+5)>0

so x-5>0 x>5 or x+5>0 x>-5 . Eithere way, the answer cannot lie in the middle. It means x is pos.

That is my take. What do you guys think?

I noticed that the signs switched in some of your explanations. I understood the sign not to change only if you are dividing or multiplying with a negative value.

Legendary Member
Posts: 1161
Joined: Mon May 12, 2008 2:52 am
Location: Sydney
Thanked: 23 times
Followed by:1 members

by mehravikas » Mon Aug 17, 2009 5:45 pm
Good Question...!!

i think answer will be C.

Statement 1 - x > -4
Statement 2 - x > 5 or x < -5

combining 1 and 2, x cannot be less than -5 otherwise statement 1 will not be true.

tngearhart wrote:I think the answer is E

If x>-4, x could be either positive or negative, Insufficent

If x>5 or x<-5, x could be either positive or negative, insufficent.

Looking at both together, we cannot tell if x>0 from the three inequalities we have.

Senior | Next Rank: 100 Posts
Posts: 37
Joined: Fri Jul 31, 2009 6:41 am
Thanked: 1 times

by acenikk » Tue Aug 18, 2009 5:07 am
I will also go with C.

Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Feb 14, 2009 9:22 am
GMAT Score:460

by GambitOS » Tue Aug 18, 2009 7:15 am
IMO A

Senior | Next Rank: 100 Posts
Posts: 66
Joined: Sun Oct 19, 2008 2:18 pm
Thanked: 1 times

Re: Is x a positive number?

by yezz » Tue Aug 18, 2009 9:40 am
EbrahimHashem wrote:Is x a positive number?

(1) x + 6>2
(2) X^2 > 25



1) x>-4...insuff

from 2
/x/>5

either

x<-5 or x>5....insuff

both
x>5...C