Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 24 May 2017, 05:56

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Is X>1? 1) x^3>x 2) x^2>x>0

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
VP
Joined: 29 Dec 2005
Posts: 1343
Followers: 10

Kudos [?]: 62 [0], given: 0

Is X>1? 1) x^3>x 2) x^2>x>0 [#permalink]

### Show Tags

19 Mar 2006, 16:39
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is X>1?
1) x^3>x
2) x^2>x>0

Last edited by Professor on 19 Mar 2006, 20:21, edited 1 time in total.
Manager
Joined: 23 Jan 2006
Posts: 192
Followers: 1

Kudos [?]: 30 [0], given: 0

### Show Tags

19 Mar 2006, 20:10
Professor wrote:
Q. Is X>1?
1) x3>x
2) x2>x>0

E.

1) x=3 3(3) = 9, 9>x
x=-3 -3(3) = -9, -9<x
INSUFFICIENT

2) x = .5
.5(2) = 1
1>.5>0
INSUFFICIENT

tegether, we still can't get any further.

E it is
VP
Joined: 21 Sep 2003
Posts: 1060
Location: USA
Followers: 3

Kudos [?]: 79 [0], given: 0

### Show Tags

19 Mar 2006, 20:16
kook44 wrote:

2) x = .5
.5(2) = 1
1>.5>0
INSUFFICIENT

tegether, we still can't get any further.

E it is

I belive Prof meant x2 => x^2. If that is true. it should be B.
_________________

"To dream anything that you want to dream, that is the beauty of the human mind. To do anything that you want to do, that is the strength of the human will. To trust yourself, to test your limits, that is the courage to succeed."

- Bernard Edmonds

GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5045
Location: Singapore
Followers: 31

Kudos [?]: 376 [0], given: 0

### Show Tags

19 Mar 2006, 20:17
1) x^3>x

x^3-x > 0
x(x^2-1)>0
x(x-1)(x+1)>0

The inequality:

-1 < x < 0
x > 1

Insufficient as we do not know which range x falls into.

2) x^2 > x > 0

- We know x must be positive
- We know x^2 must be greater than x, so x cannot be a positive fraction (e.g. 1/2)
- We know x cannot be 1 as well since this will result in x^2 = x

Sufficient.

Ans B
SVP
Joined: 14 Dec 2004
Posts: 1693
Followers: 3

Kudos [?]: 145 [0], given: 0

### Show Tags

19 Mar 2006, 20:17
Professor wrote:
Q. Is X>1?
1) x3>x
2) x2>x>0

Prof, I'm taking x3 as x^3 & x2 as x^2.

"D".
SVP
Joined: 14 Dec 2004
Posts: 1693
Followers: 3

Kudos [?]: 145 [0], given: 0

### Show Tags

19 Mar 2006, 20:25
ywilfred wrote:
1) x^3>x

x^3-x > 0
x(x^2-1)>0
x(x-1)(x+1)>0

The inequality:

-1 < x < 0
x > 1

Insufficient as we do not know which range x falls into.

2) x^2 > x > 0

- We know x must be positive
- We know x^2 must be greater than x, so x cannot be a positive fraction (e.g. 1/2)
- We know x cannot be 1 as well since this will result in x^2 = x

Sufficient.

Ans B

Wilfred & girish,

I got how you treated first condition but I have a different view here.

x^3 > x

Without solving it, if we plug & play in this equation, we easily get the range of x i.e. x>1

Reason:
1) For x < 0
x^3 < x, if x = -3, x^3 = -27

2) For 0 < x < 1
x^3 < x, if x = 0.2, x^3 = 0.008

3) For x > 1
x^3 > x, if x = 3, x^3 = 27

The only range that satisfies x^3 > x, is x > 1.

Am I missing something?
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5045
Location: Singapore
Followers: 31

Kudos [?]: 376 [0], given: 0

### Show Tags

19 Mar 2006, 20:27
I put it down as insufficient as the questions asks whether we can definitely say that x is always greater than 1. Statement 1 tells us that x does not always has to be 1, it could be -1/2 and still satisfy the inequality given in statement 1.
Manager
Joined: 20 Mar 2005
Posts: 201
Location: Colombia, South America
Followers: 1

Kudos [?]: 16 [0], given: 0

### Show Tags

19 Mar 2006, 20:30
Professor wrote:
Q. Is X>1?
1) x^3>x
2) x^2>x>0

1) insufficient

2^3 > 2

but also

-1/2 ^ 3 > -1/2

so X could be smaller than 1

2) x>0 and x^2 > 0

sufficient

I would go with B
SVP
Joined: 14 Dec 2004
Posts: 1693
Followers: 3

Kudos [?]: 145 [0], given: 0

### Show Tags

19 Mar 2006, 20:32
ywilfred wrote:
I put it down as insufficient as the questions asks whether we can definitely say that x is always greater than 1. Statement 1 tells us that x does not always has to be 1, it could be -1/2 and still satisfy the inequality given in statement 1.

Yup, got it. Thanks
I got the blunder I made!
VP
Joined: 29 Dec 2005
Posts: 1343
Followers: 10

Kudos [?]: 62 [0], given: 0

### Show Tags

19 Mar 2006, 20:36
thats correct. i updated the question.
vivek123 wrote:
Professor wrote:
Q. Is X>1?
1) x3>x
2) x2>x>0

Prof, I'm taking x3 as x^3 & x2 as x^2.

thanks guys. i donot have OA and OE. i borrowed it from here: http://www.gmatclub.com/phpbb/viewtopic.php?t=27371
Re: DS   [#permalink] 19 Mar 2006, 20:36
Display posts from previous: Sort by

# Is X>1? 1) x^3>x 2) x^2>x>0

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.