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

 It is currently 09 Feb 2016, 14:45

### 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

# what is the value of |x| (1) x=-|x| (2)x^2=4

Author Message
Manager
Joined: 05 Jun 2009
Posts: 111
Followers: 3

Kudos [?]: 105 [0], given: 4

what is the value of |x| (1) x=-|x| (2)x^2=4 [#permalink]  12 Oct 2009, 23:45
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

hi friends ,

the problem is as follow:-

what is the value of |x|

(1) x=-|x|
(2)x^2=4

please explain in details ,please provide some information on absolute value concept . i face difficulty with such
Manager
Joined: 06 Sep 2009
Posts: 115
Followers: 2

Kudos [?]: 22 [0], given: 3

Re: absolute value [#permalink]  13 Oct 2009, 02:33
sacmanitin wrote:
hi friends ,

the problem is as follow:-

what is the value of |x|

(1) x=-|x|
(2)x^2=4

please explain in details ,please provide some information on absolute value concept . i face difficulty with such

Hi sacmanitin

This is a tricky question.
First, paraphrase what is being asked:

"What is the value of |X|?" means "What is the absolute value of |x|?"
I mean, what is the distance of X from zero? (This means you can disregard the signal, whatever it is)

Let's go through the information:

(1) x = -|x|
This information alone says nothing about the distance, right?
INSUFFICIENT

(2) Xˆ2 = 4

Take the square root:
sqrt (xˆ2) = sqrt(4)

x = +- 2
You still do not know whether it is either 2 or -2
It does not matter, because both have the distance of 2 from the origin.
SUFFICIENT

Got it?

If not, PM me
Manager
Joined: 07 Jun 2009
Posts: 212
Followers: 1

Kudos [?]: 30 [0], given: 9

Re: absolute value [#permalink]  13 Oct 2009, 03:02
Absolute value or Modulus is the numerical value without the sign. Therefore modulus of -3 and 3 is 3.

1. x= -$$mod x$$
That means, since $$mod x$$ is always positive and -$$mod x$$ will be negative, therefore x is a negative number.
This is not sufficient to answer the question of, what is the value of $$mod x$$.
2. $$x^2$$= 4. this means either $$-2^2$$= 4 or $$2^2$$=4. Again we are getting 2 values of x= 2 and -2.

Now combine 1 and 2. Since x is a negative number and it has to be either 2 or -2, then x = -2

I would go for option C.
_________________

Manager
Joined: 05 Jun 2009
Posts: 111
Followers: 3

Kudos [?]: 105 [0], given: 4

Re: absolute value [#permalink]  13 Oct 2009, 04:46
this is the explanation given :-
from (1) all that can be determined is that x is negative (or 0) since |x|,the absolute value of x ,is always positive
(or 0) ,thus , (1) alone is not sufficient ,from (2) it can be detrmined that x=+/- 2 in either case |x|=2 ,sufficient
OA is B

but still if someone can explain more about explanation for statement (1) would be helpful
Director
Joined: 01 Apr 2008
Posts: 898
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 20

Kudos [?]: 443 [0], given: 18

Re: absolute value [#permalink]  13 Oct 2009, 04:53
Typical DS concept this is.
Whenever a question asks, what is the value of x ( or any variable for that matter ), it is asking what is a numeric value of that variable. So if the variable cannot have any value or if it has more than one value then we cannot answer this question.

stmt1 says that x is -ve ...x can be -1,-2,-3...but WHAT is x ? we can't say anything..so this is insuff.

stmt 2..x can be 2 or -2...but |x| will always be 2. suff.
Manager
Affiliations: CFA Level 2 Candidate
Joined: 29 Jun 2009
Posts: 221
Schools: RD 2: Darden Class of 2012
Followers: 3

Kudos [?]: 138 [0], given: 2

Re: absolute value [#permalink]  13 Oct 2009, 06:18
Agree with B

This is a tricky DS question.

Statement 1 - tells us nothing about the value, except that x is a negative number

Statement 2 - tells us x is +/- 2 normally this is insufficient but reread the original question!
Since we are looking for the absolute value it doesn't matter if 2 is +/- We know that the absolute value will be 2 regardless of the sign. So SUFFICIENT
Manager
Joined: 05 Jun 2009
Posts: 111
Followers: 3

Kudos [?]: 105 [0], given: 4

Re: absolute value [#permalink]  14 Oct 2009, 00:46
hi friends ,thanks for precise explanation ..
Re: absolute value   [#permalink] 14 Oct 2009, 00:46
Display posts from previous: Sort by