Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 39750

What is the value of x ? [#permalink]
Show Tags
23 Jul 2012, 04:43
1
This post received KUDOS
Expert's post
19
This post was BOOKMARKED
Question Stats:
52% (02:14) correct
48% (00:35) wrong based on 1649 sessions
HideShow timer Statistics



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
23 Jul 2012, 04:43
1
This post received KUDOS
Expert's post
6
This post was BOOKMARKED



Kellogg MMM ThreadMaster
Joined: 29 Mar 2012
Posts: 324
Location: India
GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38

Re: What is the value of x ? [#permalink]
Show Tags
23 Jul 2012, 05:47
1
This post received KUDOS
Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards,



Manager
Joined: 26 Dec 2011
Posts: 113

Re: What is the value of x ? [#permalink]
Show Tags
25 Jul 2012, 02:27
Please confirm if this is right logic to prove x<=0? from condition 1: x=x thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards,



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
27 Jul 2012, 07:31



Intern
Joined: 11 Apr 2012
Posts: 38

Re: What is the value of x ? [#permalink]
Show Tags
29 Jul 2012, 06:58
Cyberjadugar/Bunuel, is Pavan puneets approach right to confirm stmt ( 1) leads us to x<=0 ? can you just break stmt 1 down for us a little please ? pavanpuneet wrote: Please confirm if this is right logic to prove x<=0? from condition 1: x=x
thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x
Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards,



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
29 Jul 2012, 07:29
vinay911 wrote: Cyberjadugar/Bunuel, is Pavan puneets approach right to confirm stmt ( 1) leads us to x<=0 ? can you just break stmt 1 down for us a little please ? pavanpuneet wrote: Please confirm if this is right logic to prove x<=0? from condition 1: x=x
thus, if x>0 ==> x=x ==> 2x=0 ==> x=0 and if x<0 ==> x=(x) ==> x=x...however x<0, then for this condition x will be always less than zero to satisfy x=x
Thus in combination x<=0. cyberjadugar wrote: Hi,
Difficulty level: 600
Using (1), x = x or \(x \leq 0\), Insufficient.
Using (2), \(x^2 = 4\) or x = 2. Sufficient.
Answer (B)
Regards, From (1) we can conclude that \(x\leq{0}\) (check this: whatisthevalueofx136195.html#p1108170), though the approach you are referring to is not precise enough.
_________________
New to the Math Forum? Please read this: All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 26 Dec 2011
Posts: 113

Re: What is the value of x ? [#permalink]
Show Tags
29 Jul 2012, 07:50
Hi Bunuel, Can you please let me know where I have made the mistake to derive x<=0. It will be really helpful. Thanks.



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
29 Jul 2012, 08:10
pavanpuneet wrote: Hi Bunuel, Can you please let me know where I have made the mistake to derive x<=0. It will be really helpful. Thanks. Sure. If we do the way you are proposing then we should consider two cases: If \(x\leq{0}\), then we would have that \(x=(x)\) > \(x=x\), which is obviously true. So, \(x=x\) holds true for any \(x\) which is \(\leq{0}\); If \(x>{0}\), then we would have that \(x=x\) > \(2x=0\) > \(x=0\), which is not a valid solution since we are considering the range when \(x>{0}\). So, if \(x>{0}\) then \(x=x\) has no valid solutions. Therefore, from the above we have that \(x=x\) holds true only when \(x\leq{0}\). Now, you could conclude that right away, since we can rewrite \(x=x\) as \(x=x\), which according to the properties of absolute value is true for \(x\leq{0}\). Hope it's clear.
_________________
New to the Math Forum? Please read this: All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 14 Aug 2012
Posts: 5

Re: What is the value of x ? [#permalink]
Show Tags
17 Aug 2012, 06:01
I understand the answer explanation, so thanks to everyone who contributed. But what I'm confused is when they use the term "value." Does that always mean they are looking for a single number?



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
17 Aug 2012, 06:17



Manager
Joined: 04 Mar 2013
Posts: 88
Location: India
Concentration: General Management, Marketing
GPA: 3.49
WE: Web Development (Computer Software)

Re: What is the value of x ? [#permalink]
Show Tags
16 May 2013, 09:27
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectWhat is the value of x ? (1) x =  x (2) x^2 = 4 Practice Questions Question: 1 Page: 275 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you! Stmt 1: no value, stmt2: x = 2 or 2 and !x! = 2, so answer i stmt B alone



Manager
Joined: 25 Jul 2012
Posts: 75
Location: United States

Re: What is the value of x ? [#permalink]
Show Tags
27 Aug 2013, 05:12
Hello, I need help understanding and visualizing the absolute value concept of \(x=x\) For example: \(x=3\) we know that on the number line \(x\) is exactly 3 units away from zero \(x=3\) or \(x=3\) How do we translate \(x=x\)? \(x\) is exactly \(x\) units away from zero? \(x=x\) or \(x=x\)? So when I break statement one down in to further steps I get: \(x=x\) \(+x=x\) or \(x=x\) \(x=x\) or \(x=x\)? I think I am wrong here though? Because how can \(x\leq{0}\)? I would really like to master this concept down. If you have similar questions with \(x=x\) being tested, please post thanks
_________________
If my post has contributed to your learning or teaching in any way, feel free to hit the kudos button ^_^



Intern
Joined: 05 Dec 2013
Posts: 16

Re: DS question from OG [#permalink]
Show Tags
30 Dec 2013, 12:07
1
This post was BOOKMARKED
seabhi wrote: 1. What is the value of x ?
(1) x = –x (2) x2 = 4
Posting OG question, did not find in the search. First off, this is a "value" DS question therefore in order to be sufficient, we must be able to calculate a specific value for x S1: x could be a suite of numbers such as: any negative integer or fraction, and 0 > not sufficientS2: 2x = 4  therefore x = 2 > sufficient because we know the value of x, and can now answer the question stem x > 2 = 2 Let me know if this helps!



Intern
Joined: 02 Mar 2013
Posts: 3

Re: What is the value of x ? [#permalink]
Show Tags
30 May 2014, 11:00
Hi,
I've got a big dilemma for this question.
For statement 2 x^2=4
I see 3 solution fitting: i) x=2 >> 2^2=4 therefore abs(2)=2
ii) x=(2) >> (2)^2=4 therefore abs(2)=2
BUT iii) sx=qr(4) >>> sqr(4)^2=4. Am I not correct on this? The sterm/question does not say that x has to be an integer right? So sqr(4) can fit in here, isn't it? therefore abs(sqr(4))=sqr(4)
Therefore statement 2 is insufficient.
Between the OG and Online explanations, I do not understand why sqr(4) could not fit in statement 2.
Thx



Math Expert
Joined: 02 Sep 2009
Posts: 39750

Re: What is the value of x ? [#permalink]
Show Tags
30 May 2014, 11:04



Intern
Joined: 02 Mar 2013
Posts: 3

Re: What is the value of x ? [#permalink]
Show Tags
30 May 2014, 11:09
Hmm I am tired... I should have seen that! Thanks Bunuel



Director
Status: Tutor  BrushMyQuant
Joined: 05 Apr 2011
Posts: 619
Location: India
Concentration: Finance, Marketing
GMAT 1: 570 Q49 V19 GMAT 2: 700 Q51 V31
GPA: 3
WE: Information Technology (Computer Software)

Re: Ab value [#permalink]
Show Tags
27 Sep 2014, 09:10
janani28 wrote: What is the value of x?
(1) x = x (2) x2 = 4 STAT1 x = x => x = x It just tells us that x is a negative number or zero So, INSUFFICIENT STAT2 x^2 = 4 means x = +2 So, x = 2 So, SUFFICIENT So, Answer will be B Hope it helps!
_________________
Ankit
Check my Tutoring Site > Brush My Quant
GMAT Quant Tutor How to start GMAT preparations? How to Improve Quant Score? Gmatclub Topic Tags Check out my GMAT debrief
How to Solve : Statistics  Reflection of a line  Remainder Problems  Inequalities



eGMAT Representative
Joined: 04 Jan 2015
Posts: 726

Re: What is the value of x ? [#permalink]
Show Tags
07 May 2015, 22:52
1
This post received KUDOS
Expert's post
1
This post was BOOKMARKED
A few students above had difficulty in processing the first statement: x = x Here's how you can think through this statement visually: x denotes the distance of an unknown number x from the zero point on the number line. Being the distance, x is always nonnegative. (Please note that it will be wrong to say that the distance x is always positive, because the word 'positive' means 'strictly greater than zero'. It is possible that a point lies ON the zero point, thereby making its distance from the zero point equal to zero. )
So, x = ()(a positive number) = (a negative number) Or, x can be equal to zero (that is, on the number line, point x lies ON the point zero. Therefore, x = distance between 0 and x = 0 as well) The important takeaway is that when processing equations of the type x = x etc., start by first considering that x is nonnegative, since it represents the distance of a number from the zero point on the number line.Hope this helps! Japinder
_________________
 '4 out of Top 5' Instructors on gmatclub  70 point improvement guarantee  www.egmat.com



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 1158
Location: United States (CA)

Re: What is the value of x ? [#permalink]
Show Tags
21 Jul 2016, 10:43
Bunuel wrote: What is the value of x ?
(1) x =  x (2) x^2 = 4 We need to determine the absolute value of x. Statement One Alone:x = x If x = x, then x must be negative or 0. For example, if x = 3, 3 = 3. However, since we do not have an exact value for x, statement one is not sufficient. We can eliminate answer choices A and D. Statement Two Alone:x^2 = 4 We can simplify by taking the square root of both sides of the equation: √x^2 = √4 x = 2 Since we have 2 as the value for x, this answers the question. Answer: B
_________________
Scott WoodburyStewart
Founder and CEO
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions




Re: What is the value of x ?
[#permalink]
21 Jul 2016, 10:43







