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

 It is currently 30 Aug 2016, 14:30

### 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 do we do when we take combined case in inequalities?

Author Message
TAGS:

### Hide Tags

Intern
Joined: 12 Aug 2011
Posts: 4
Followers: 0

Kudos [?]: 3 [1] , given: 1

what do we do when we take combined case in inequalities? [#permalink]

### Show Tags

17 Aug 2011, 05:36
1
KUDOS
00:00

Difficulty:

(N/A)

Question Stats:

38% (01:01) correct 63% (00:26) wrong based on 8 sessions

### HideShow timer Statistics

Is |x-1| < 1?

(1) (x-1)^2 <= 1
(2) x^2 - 1 > 0

Hi someone help solve this, shouldnt be very difficult.

I know how to evaluate statement 1 and statement 2, looking to just understand how do we test a combined statement i,e C when we have multiple inequality equations. Do we test 4 values...

Maybe somebody could explain while solving this question..

Once again how do we evaluate c- statement combined together..is my main concern

Thanks
Kaps
[Reveal] Spoiler: OA
Manager
Joined: 28 May 2011
Posts: 195
Location: United States
GMAT 1: 720 Q49 V38
GPA: 3.6
WE: Project Management (Computer Software)
Followers: 2

Kudos [?]: 57 [0], given: 7

Re: what do we do when we take combined case in inequalities? [#permalink]

### Show Tags

17 Aug 2011, 10:24
First I did calculation partially and got the answer C, but than when I was trying to type solution for you, I get more insight into the question.

We need to prove

Is |x-1| < 1? => -1<(x-1)<1 => 0<x<2 ?

(1) (x-1)^2 <= 1

=> 0 <= X <= 2 (Correction in earlier calculation)
=> Doesn't prove 0<x<2, Not Sufficient

(2) x^2 - 1 > 0

=> (x > -1 and x > 1) OR (x < -1 and x < 1)
=> x > 1 or x < -1
=> Doesn't prove 0<x<2, Not Sufficient

Combining these two we get

1 < X <= 2

=> Doesn't prove 0<x<2, because x = 2 is a possible solution in combined equality.

_________________

-------------------------------------------------------------------------------------------------------------------------------
http://gmatclub.com/forum/a-guide-to-the-official-guide-13-for-gmat-review-134210.html
-------------------------------------------------------------------------------------------------------------------------------

Last edited by anordinaryguy on 17 Aug 2011, 11:06, edited 1 time in total.
Director
Joined: 03 May 2007
Posts: 886
Schools: University of Chicago, Wharton School
Followers: 6

Kudos [?]: 145 [0], given: 7

Re: what do we do when we take combined case in inequalities? [#permalink]

### Show Tags

17 Aug 2011, 10:33
mokap25 wrote:
Is |x-1| < 1?

(1) (x-1)^2 <= 1
(2) x^2 - 1 > 0

From statement 1: If (x-1)^2 <= 1, the value of x varies from 0 to 2 i.e. x is non-negative.

(x-1)^2 <= 1
(x-1) (x-1) <= 1

i) x-1 <= 1
x-1 <= 1
x <= 2

If x is 2, |x-1| = |2-1| = 1 ..........No.
If x is 1.5, |x-1| = |1.5-1| = 0.5.. Yes.

ii) x-1 => 1
x => 0

If x is 0, |x-1| = |0-1| = 1 ..........No.
If x is 0.5, |x-1| = |0.5-1| = 0.5.. Yes.

Not sufficient......

From statement 2: x^2 - 1 > 0
x^2 > 1

i) either, x > 1
ii) or x < -1

If x is 1.1, |x-1| = |1.1-1| = 0.1 .......... yes.
If x is -1.1, |x-1| = |-1.1-1| = -2.1. No.

From 1 and 2: the value of x varies from 0 to 2 but still insufficient.

E.
Intern
Joined: 05 Mar 2011
Posts: 7
Followers: 0

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

Re: what do we do when we take combined case in inequalities? [#permalink]

### Show Tags

17 Aug 2011, 11:43
Both Statements 1 & 2 (Individually & Combined) yields range of numbers that do not satisfy the Question Stem.

We can simplyfy the question stem
Is |x-1| < 1? to
Is 0<x<2 to fit and check the range of numbers yielded by the statement 1 & 2.
Also X can be a fraction which further increases the possible value ranges of X .

So I agree with Answer E.
Manager
Status: Quant 50+?
Joined: 02 Feb 2011
Posts: 107
Concentration: Strategy, Finance
Schools: Tuck '16, Darden '16
Followers: 1

Kudos [?]: 28 [0], given: 22

Re: what do we do when we take combined case in inequalities? [#permalink]

### Show Tags

18 Aug 2011, 07:37
I struggled a lot with these types of questions and actually drawing a number line helped me a lot.

If we look at the question we know either (1), (2) or (1)+(2) must prove 0<x<2. Draw that on a line, compare it to (1), (2) and then for c, compare whether the range of (1) + (2)'s (where 1 & 2 overlap) falls purely in 0<x<2.
Re: what do we do when we take combined case in inequalities?   [#permalink] 18 Aug 2011, 07:37
Similar topics Replies Last post
Similar
Topics:
Inequality 2 04 Jun 2011, 12:53
5 We are given two integers a and b 3 01 Apr 2013, 01:05
If we have x^2 > 1 What does this mean ?? x> 1 or 6 10 Jul 2011, 02:44
2 At what angle do lines y = Kx + B and y = Bx + K intersect ? 7 29 Dec 2009, 21:28
7 Let's do this one 5 31 Aug 2009, 04:29
Display posts from previous: Sort by