It is currently 21 Sep 2017, 16:36

### 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

# m22#3

Author Message
Senior Manager
Joined: 20 Feb 2008
Posts: 295

Kudos [?]: 49 [1], given: 0

Location: Bangalore, India
Schools: R1:Cornell, Yale, NYU. R2: Haas, MIT, Ross

### Show Tags

26 Nov 2008, 19:54
1
KUDOS
2
This post was
BOOKMARKED
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

Kudos [?]: 49 [1], given: 0

SVP
Joined: 29 Aug 2007
Posts: 2473

Kudos [?]: 832 [2], given: 19

### Show Tags

26 Nov 2008, 21:49
2
KUDOS
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

1: x = -1 or 0 or 1.

i. if x is +ve,
x^4 = x
x^4 - x = 0
x (x^3 - 1) = 0
x = 0, and x^3 = 1 or x = 1.

ii: if x is -ve,
x^4 = -x
x^4 + x = 0
x (x^3 + 1) = 0
x = 0, and x^3 = -1 or x = -1.
so not suff...

2: x could be anything other than 0 and a +ve fraction.

x^2 > x
x^2 - x > 0
x (x-1) > 0
if x is a +ve (x-1) is also a +ve.
i: x > 0 .......... not possible.

ii: x - 1 > 0
x >1 ............... possible.
so x > 1.

if x is a -ve (x-1) is also a -ve.
i: x < 0 .............. possible.

ii: x < 1 ............... not possible.
so x <0.

1&2: x has to be -1.
so C.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Kudos [?]: 832 [2], given: 19

Intern
Joined: 15 Nov 2009
Posts: 31

Kudos [?]: 12 [0], given: 0

Location: Moscow, Russia

### Show Tags

30 Dec 2009, 06:56
The graphs of y=x^4 and y=|x| 1ntersect each other at three points (-1,1), (0,0) and (1,1), then A is wrong. Any x<0 or x>1 satisfies the inequality x^2>x, then B is wrong.
Both statements together uniquely determine the value x=-1, so C is the answer.

Last edited by nvgroshar on 31 Dec 2009, 15:21, edited 1 time in total.

Kudos [?]: 12 [0], given: 0

Manager
Joined: 04 Dec 2009
Posts: 70

Kudos [?]: 9 [0], given: 4

Location: INDIA

### Show Tags

30 Dec 2009, 21:01
ANS:E from both statement we can conclude only x>1 not a single value.
_________________

MBA (Mind , Body and Attitude )

Kudos [?]: 9 [0], given: 4

Intern
Joined: 03 Aug 2009
Posts: 1

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

### Show Tags

30 Dec 2009, 22:52
It should be C. I thought it E though

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

Manager
Joined: 20 Oct 2009
Posts: 107

Kudos [?]: 49 [0], given: 0

### Show Tags

01 Jan 2010, 07:29
1 is not sufficient - x could be 0 or 1, -1
2 X^2>X which means x(x-1)>0 x>1 or x<0

Combine 1 and 2, x=-1
_________________

Dream the impossible and do the incredible.

Live. Love. Laugh.

Kudos [?]: 49 [0], given: 0

Manager
Joined: 05 Dec 2009
Posts: 126

Kudos [?]: 87 [1], given: 0

### Show Tags

13 Mar 2010, 17:12
1
KUDOS
When combine both the stmt, we get x = -1, so IMO Ans should be C.

Kudos [?]: 87 [1], given: 0

Manager
Joined: 13 Dec 2009
Posts: 249

Kudos [?]: 233 [0], given: 13

### Show Tags

19 Mar 2010, 08:13
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

stmt1L x^4 = x or x^4 = -x
x(x^3-1)=0 or x(x^3+1) =0
so x = 0, -1,1

stmt2: x^2 > x => x(x-1)>0 insuff
combine both. x <>0 or 1 so x is -1
_________________

My debrief: done-and-dusted-730-q49-v40

Kudos [?]: 233 [0], given: 13

Intern
Status: "You never fail until you stop trying." ~Albert Einstein~
Joined: 16 May 2010
Posts: 30

Kudos [?]: 4 [0], given: 7

### Show Tags

06 Jan 2011, 09:39
What is the value of x ?

1. x^4 = |x|

X can equal 1 or -1 or 0 (IS)

2. x^2 > x

x(x-1)>0 (IS)

Both: You can conclude that X is -1 using st.2 to validate it.

Kudos [?]: 4 [0], given: 7

Intern
Joined: 30 Jul 2010
Posts: 11

Kudos [?]: 14 [1], given: 1

### Show Tags

06 Jan 2011, 10:39
1
KUDOS
C

From option A, x can be 0 or 1 or -1.
From option B , x can be any negative integer. And it can be any negative fraction value.

Using both we can deduce x value as -1.

Hence the option is c.

Kudos [?]: 14 [1], given: 1

Senior Manager
Joined: 01 Nov 2010
Posts: 285

Kudos [?]: 85 [0], given: 44

Location: India
Concentration: Technology, Marketing
GMAT Date: 08-27-2012
GPA: 3.8
WE: Marketing (Manufacturing)

### Show Tags

06 Jan 2011, 10:42
x= -1,
excellent explanation were given above.
_________________

kudos me if you like my post.

Attitude determine everything.
all the best and God bless you.

Kudos [?]: 85 [0], given: 44

Senior Manager
Joined: 19 Oct 2010
Posts: 256

Kudos [?]: 87 [0], given: 27

Location: India
GMAT 1: 560 Q36 V31
GPA: 3

### Show Tags

18 Feb 2011, 01:24
I concur with the OA.

Stmt 1 tells you it is +1 or -1
Stmt 2 tells you it is an integer

Combining the two stmts you can tell that the only possible fit is -1. Therefore, it is C.
_________________

petrifiedbutstanding

Kudos [?]: 87 [0], given: 27

Director
Joined: 01 Feb 2011
Posts: 726

Kudos [?]: 140 [0], given: 42

### Show Tags

14 Apr 2011, 18:05
1. Not sufficient
When x is +ve x = 1
When x is -ve x = -1

2. Not sufficient
x<0 or x>1

together we have x = -1. Sufficient.

Kudos [?]: 140 [0], given: 42

Manager
Joined: 14 Feb 2011
Posts: 185

Kudos [?]: 147 [0], given: 3

### Show Tags

14 Apr 2011, 22:49
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

This one is interesting as the answer is different if you do not know that its a GMAT question.

From statement 1, on squaring both sides we get $$x^8 = x^2$$
or $$x^2*(x^6-1) = 0$$

so, $$x = 0$$ or $$x^6 = 1$$.

Now $$x^6 = 1$$ has six roots and the six sixth roots of unity are ±1, and (±1 ± i√3)/2.

My confusion arose because i considered the complex roots as well and hence my initial reaction was that answer is E.

I guess on GMAT you can go along with only real roots and in that case, answer is indeed C.

Kudos [?]: 147 [0], given: 3

Math Expert
Joined: 02 Sep 2009
Posts: 41666

Kudos [?]: 124360 [2], given: 12077

### Show Tags

10 Jan 2013, 06:03
2
KUDOS
Expert's post
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

What is the value of $$x$$ ?

(1) $$x^4 = |x|$$. This statement implies that $$x=-1$$, $$x=0$$, or $$x=1$$. Not sufficient.

(2) $$x^2> x$$. Rearrange and factor out $$x$$ to get $$x(x-1)>0$$. The roots are $$x=0$$ and $$x=1$$, "$$>$$" sign means that the given inequality holds true for: $$x<0$$ and $$x>1$$. Not sufficient.

(1)+(2) The only value of $$x$$ from (1) which is in the range from (2) is $$x=-1$$. Sufficient.

_________________

Kudos [?]: 124360 [2], given: 12077

Intern
Joined: 14 Jul 2012
Posts: 15

Kudos [?]: 5 [0], given: 8

Location: United States
GPA: 3.3
WE: Information Technology (Computer Software)

### Show Tags

11 Jan 2013, 01:14
Answer C (by taking option 1+ 2).

Kudos [?]: 5 [0], given: 8

Director
Status: Gonna rock this time!!!
Joined: 22 Jul 2012
Posts: 511

Kudos [?]: 71 [0], given: 562

Location: India
GMAT 1: 640 Q43 V34
GMAT 2: 630 Q47 V29
WE: Information Technology (Computer Software)

### Show Tags

21 Feb 2013, 07:08
Bunuel wrote:
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

What is the value of $$x$$ ?

(1) $$x^4 = |x|$$. This statement implies that $$x=-1$$, $$x=0$$, or $$x=1$$. Not sufficient.

(2) $$x^2> x$$. Rearrange and factor out $$x$$ to get $$x(x-1)>0$$. The roots are $$x=0$$ and $$x=1$$, "$$>$$" sign means that the given inequality holds true for: $$x<0$$ and $$x>1$$. Not sufficient.

(1)+(2) The only value of $$x$$ from (1) which is in the range from (2) is $$x=-1$$. Sufficient.

Bunuel/Karishma
I dont understand the following:

The roots are $$x=0$$ and $$x=1$$, "$$>$$" sign means that the given inequality holds true for: $$x<0$$ and $$x>1$$.

shouldn't $$x(x-1)>0$$ mean that x>0 or (x-1)>0 ?
Please explain why it means x<0 ?
_________________

hope is a good thing, maybe the best of things. And no good thing ever dies.

Who says you need a 700 ?Check this out : http://gmatclub.com/forum/who-says-you-need-a-149706.html#p1201595

My GMAT Journey : http://gmatclub.com/forum/end-of-my-gmat-journey-149328.html#p1197992

Kudos [?]: 71 [0], given: 562

Math Expert
Joined: 02 Sep 2009
Posts: 41666

Kudos [?]: 124360 [0], given: 12077

### Show Tags

21 Feb 2013, 07:19
Sachin9 wrote:
Bunuel wrote:
ventivish wrote:
What is the value of $$x$$ ?

1. $$x^4 = |x|$$
2. $$x^2 \gt x$$

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

What is the value of $$x$$ ?

(1) $$x^4 = |x|$$. This statement implies that $$x=-1$$, $$x=0$$, or $$x=1$$. Not sufficient.

(2) $$x^2> x$$. Rearrange and factor out $$x$$ to get $$x(x-1)>0$$. The roots are $$x=0$$ and $$x=1$$, "$$>$$" sign means that the given inequality holds true for: $$x<0$$ and $$x>1$$. Not sufficient.

(1)+(2) The only value of $$x$$ from (1) which is in the range from (2) is $$x=-1$$. Sufficient.

Bunuel/Karishma
I dont understand the following:

The roots are $$x=0$$ and $$x=1$$, "$$>$$" sign means that the given inequality holds true for: $$x<0$$ and $$x>1$$.

shouldn't $$x(x-1)>0$$ mean that x>0 or (x-1)>0 ?
Please explain why it means x<0 ?

Check here:
x2-4x-94661.html#p731476,
inequalities-trick-91482.html,
everything-is-less-than-zero-108884.html?hilit=extreme#p868863,
_________________

Kudos [?]: 124360 [0], given: 12077

Manager
Joined: 28 Apr 2013
Posts: 154

Kudos [?]: 75 [0], given: 84

Location: India
GPA: 4
WE: Medicine and Health (Health Care)

### Show Tags

06 Jan 2014, 06:26
OA-C since neither condition 1 nor 2 satisfies the Q to solve x.

Thanks

_________________

Thanks for Posting

LEARN TO ANALYSE

+1 kudos if you like

Kudos [?]: 75 [0], given: 84

Intern
Joined: 03 Jan 2014
Posts: 2

Kudos [?]: [0], given: 1

### Show Tags

07 Jan 2014, 00:45
statement 1 , x=-1,0,1 NOT SUFFICIENT STATEMENT 2 Not sufficient as universally true, COMBINING statement1& 2 , we found is true for x=-1 hence ans C

Kudos [?]: [0], given: 1

Re: m22#3   [#permalink] 07 Jan 2014, 00:45

Go to page    1   2    Next  [ 21 posts ]

Display posts from previous: Sort by

# m22#3

Moderator: Bunuel

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.