Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 25 May 2013, 21:39

# Is x^2 > 15? (1) x > -4 (2) x^3 < 0

Author Message
TAGS:
SVP
Joined: 01 Sep 2010
Posts: 1747
Followers: 56

Kudos [?]: 585 [0], given: 467

Is x^2 > 15? (1) x > -4 (2) x^3 < 0 [#permalink]  22 May 2012, 14:51
00:00

Question Stats:

50% (02:18) correct 50% (00:15) wrong based on 0 sessions
Is x^2 > 15?

(1) x > -4
(2) x^3 < 0
[Reveal] Spoiler: OA

_________________

KUDOS is the good manner to help the entire community.

GMAT Club team member
Joined: 02 Sep 2009
Posts: 11628
Followers: 1802

Kudos [?]: 9614 [1] , given: 829

Re: Is x^2 > 15? (1) x > -4 (2) x^3 < 0 [#permalink]  22 May 2012, 15:04
1
KUDOS
Is x^2 > 15?

Is x^2>15? --> is x<-\sqrt{15} or is x>\sqrt{15}?

(1) x > -4 --> if -4<x<-\sqrt{15} or if x>\sqrt{15} then the answer is YES but if -\sqrt{15}\leq{x}\leq{\sqrt{15}} then the answer is NO. Not sufficient.

(2) x^3 < 0 --> x<0 --> if x<-\sqrt{15} then the answer is YES but if -\sqrt{15}\leq{x}<0 then the answer is NO. Not sufficient.

(1)+(2) x>-4 and x<0 --> -4<x<0 --> if -4<x<-\sqrt{15} then the answer is YES but if -\sqrt{15}\leq{x}<0 then the answer is NO. Not sufficient.

Hope it's clear.
_________________
SVP
Joined: 01 Sep 2010
Posts: 1747
Followers: 56

Kudos [?]: 585 [0], given: 467

Re: Is x^2 > 15? (1) x > -4 (2) x^3 < 0 [#permalink]  22 May 2012, 15:41
maybe is a bit comfortable to work with number on a number line instead of \sqrt{15} (is the same after all)

1) x > - 4 -----> -3,9 is largest than 15 but -3 NO but again +5 yes insuff

2) x^3 < 0 ---> x is negative -----> -1 is NO -5 is YES Insuff

1) + 2) we have only negative value but -1 is YES -3.9 is NO -----> E

Thanks Bunuel .
_________________

KUDOS is the good manner to help the entire community.

Re: Is x^2 > 15? (1) x > -4 (2) x^3 < 0   [#permalink] 22 May 2012, 15:41
Similar topics Replies Last post
Similar
Topics:
X>0? 1)X^3 < X^2 2)X^3 < X^4 18 09 Nov 2004, 02:41
Is 1+x+x^2+x^3+x^4 > 1/(1-x) ? 1). x > 0 2). x < 1 6 04 Feb 2006, 23:13
Is 1+x+x^2+x^3+x^4 > 1/(1-x) ? (1) x > 0 (2) x < 1 6 25 Feb 2006, 22:36
Is 1+x+x^2+x^3+x^4 > 1/ (1-x)? (1) x > 0 (2) x < 1 1 04 Mar 2006, 22:22
Is 1+x+x^2+x^3+x^4>1/(1-x)? 1). x>0 2). x<1 4 04 Jun 2009, 11:34
Display posts from previous: Sort by