It is currently 21 Oct 2017, 06:02

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is |x| = y - z ? (1) x + y = z (2) x < 0

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Director
Director
User avatar
Joined: 10 Mar 2013
Posts: 593

Kudos [?]: 461 [0], given: 200

Location: Germany
Concentration: Finance, Entrepreneurship
GMAT 1: 580 Q46 V24
GPA: 3.88
WE: Information Technology (Consulting)
GMAT ToolKit User
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 13 Dec 2015, 11:39
DenisSh wrote:
Is |x| = y - z ?

(1) x + y = z
(2) x < 0


Question: x=y-z (when x is +ve) or x=z-y (when x is -ve)
(1) x=z-y, we don't know the sign of x
(2) clearly not sufficient
(1) + (2) from (2) we know that x<0 --> in this case |x| = y - z is equal to x=z-y and (1) gives us this expression
Answer C
_________________

When you’re up, your friends know who you are. When you’re down, you know who your friends are.

Share some Kudos, if my posts help you. Thank you !

800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50
GMAT PREP 670
MGMAT CAT 630
KAPLAN CAT 660

Kudos [?]: 461 [0], given: 200

Intern
Intern
avatar
B
Joined: 09 Sep 2015
Posts: 3

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

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 19 Dec 2015, 13:39
Hi Bunnel- It might sound lame, but why do we need to consider 2 cases for statement 1? Why can we not simply consider x= z-y which means z>y while we are testing for whether y>equal to Z and hence statement 1 is sufficient.

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

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16605

Kudos [?]: 273 [0], given: 0

Premium Member
Re: Is IxI = y –z? [#permalink]

Show Tags

New post 20 Apr 2016, 13:32
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 273 [0], given: 0

1 KUDOS received
Intern
Intern
User avatar
Status: Pursuit of Happiness
Joined: 10 Sep 2016
Posts: 31

Kudos [?]: 41 [1], given: 62

Location: United States (IL)
Concentration: Finance, Economics
Schools: HBS '19, CBS '19
GMAT 1: 590 Q44 V27
GMAT 2: 690 Q50 V34
GPA: 3.94
Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 20 Oct 2016, 11:29
1
This post received
KUDOS
yashrakhiani wrote:
IS |x| = y -z??

1)x+ y = z


2)x<0


Answer is C.

From the question,
if x>0, x = y-z
if x<0, x = -(y-z) = z-y

Let's start with the easy statement - Statement 2.

(2): Insufficient
x<0 doesn't give us any information about y and z. Eliminate B and D

(1): Insufficient
Statement 1 says that x = z - y
If x<0 , then the answer is yes since |x| will be equal to y-z
if x>0, then the answer is no since |x| = z-y
We have a Yes and a No. Eliminate A.

(1) and (2) together: Sufficient
We have x<0 and x = z - y. hence, |x| = y-z

--
Need 3 Kudos
_________________

If you find this post hepful, please press +1 Kudos

Kudos [?]: 41 [1], given: 62

Intern
Intern
avatar
Joined: 30 Jun 2016
Posts: 17

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

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 28 Oct 2016, 23:19
I have a doubt here.
if we see,
if x is +ve then x=y-z and if x is -ve x+y = z.

st 1 says x+y = z , so why cant A be suff

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

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 41891

Kudos [?]: 129095 [0], given: 12194

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 29 Oct 2016, 00:41
vsvikas wrote:
I have a doubt here.
if we see,
if x is +ve then x=y-z and if x is -ve x+y = z.

st 1 says x+y = z , so why cant A be suff


(1) says that -x = y - z. For this case, |x| = y - z would be true ONLY IF x is negative but if x is positive, then |x| = y - z would not be true.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | 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?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 129095 [0], given: 12194

Intern
Intern
avatar
Joined: 30 Jun 2016
Posts: 17

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

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 29 Oct 2016, 01:04
per st 1, when x + y = z, this will happen when x<=0, so this st is sufficient. as when x<=0, then |x|=y-z
where am i going wrong or am confusing some concept

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

Intern
Intern
avatar
B
Joined: 21 Dec 2015
Posts: 26

Kudos [?]: 3 [0], given: 29

WE: Account Management (Commercial Banking)
Premium Member CAT Tests
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 01 Nov 2016, 08:02
Bunuel : Is mod x = y-z

I interpreted the question as " Is x = +(y-z) or x= -(y -z)?"

And hence, since the first option mentions x = -y+z, i chose A. Am i missing something?

Kudos [?]: 3 [0], given: 29

Senior Manager
Senior Manager
User avatar
B
Status: DONE!
Joined: 05 Sep 2016
Posts: 408

Kudos [?]: 23 [0], given: 283

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 01 Nov 2016, 12:36
Tricky, but do-able:

(1) x+y = z

Ex 1: -2+3=1 --> 3-1=2 --> works *

Ex 2: 3+(-2)=1 = --> -2-1=-3 --> fail (we don't get absolute value)

Ex 3: 3+5=8 --> 5-8=-3 --> fail

We can see a pattern from Ex 2 and 3 that x must be negative in order for this to work.

NOT SUFFICIENT

(2) x<0 --> NOT SUFFICIENT by itself

(1)+(2) --> SUFFICIENT

Kudos [?]: 23 [0], given: 283

Director
Director
User avatar
G
Joined: 26 Oct 2016
Posts: 694

Kudos [?]: 180 [0], given: 855

Location: United States
Concentration: Marketing, International Business
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 08 Feb 2017, 20:52
EvaJager wrote:
sayak636 wrote:
Is |X|= Y- Z?

1. X+Y= Z
2. X< 0


(1) Can be rewritten as X = -Y + Z, so |X| = |-Y + Z|, which would be equal to Y - Z, if and only if \(-Y+Z\leq0\). Obviously, we don't know that, so (1) insufficient.
(2) Cannot be sufficient, it doesn't say anything about Y and Z.
(1) and (2) together: X = -Y + Z < 0, therefore |X| = Y - Z, sufficient.

Answer: C


Hello Eva,

Can you please explain how do you reach to below conclusion :

"(1) and (2) together: X = -Y + Z < 0, therefore |X| = Y - Z, sufficient."
_________________

Thanks & Regards,
Anaira Mitch

Kudos [?]: 180 [0], given: 855

Director
Director
User avatar
P
Joined: 05 Mar 2015
Posts: 964

Kudos [?]: 287 [0], given: 41

Is |x| = y - z? [#permalink]

Show Tags

New post 06 Mar 2017, 19:19
sitagupta385 wrote:
Is |x| = y - z?

1) x + y = z
2) x < 0



is
x= y-z && x= z-y ??

(1) x= z-y ...but we dont know whether x= y-z..
insuff

(2) x<0
so x= z-y but we dont know x= y-z or not..
insuff

combining we know x= y-z (from 1) && x= y-z(from2)
thus |x| = y - z
suff

Ans C

Kudos [?]: 287 [0], given: 41

Intern
Intern
avatar
B
Joined: 03 Jan 2017
Posts: 30

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

Re: Is |x| = y - z? [#permalink]

Show Tags

New post 06 Mar 2017, 20:21
1. X+Y=Z
-x=y-z
|x|=y-z
Ans a.

Hit kudos if i this solution is ryt.

Sent from my MotoG3 using GMAT Club Forum mobile app

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

Manager
Manager
avatar
S
Joined: 29 May 2016
Posts: 132

Kudos [?]: 17 [0], given: 345

CAT Tests
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 07 Mar 2017, 22:56
Bunuel , i have one doubt in this question. i have gone through the explanations in chain, still not clear.

suppose we have been asked in question ...
is |x|=1 ? according to explanations it says x=-1 && x=1 ?
A) x=1 .... so this must be insufficient.

please correct me if I am missing anything.

Kudos [?]: 17 [0], given: 345

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 41891

Kudos [?]: 129095 [1], given: 12194

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 08 Mar 2017, 00:21
1
This post received
KUDOS
Expert's post
mbaprep2016 wrote:
Bunuel , i have one doubt in this question. i have gone through the explanations in chain, still not clear.

suppose we have been asked in question ...
is |x|=1 ? according to explanations it says x=-1 && x=1 ?
A) x=1 .... so this must be insufficient.

please correct me if I am missing anything.


So, the question is:

Does |x| = 1?

(1) x = 1. This would be sufficient because |1| = 1 and we would have a definite YES answer to the question.

Hope it helps.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | 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?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 129095 [1], given: 12194

Senior Manager
Senior Manager
avatar
B
Joined: 05 Jan 2017
Posts: 435

Kudos [?]: 59 [0], given: 15

Location: India
Premium Member
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 08 Mar 2017, 05:17
St 1: y-z = -x. if x is positive |x| = z-y. if x is negative, |x| = y-z. INSUFFICIENT
St 2: x is negative. no idea about y and z. INSUFFICIENT

St 1 & St 2: y-z = -x. x is negative. hence |x| = y-z. ANSWER

Option C

Kudos [?]: 59 [0], given: 15

1 KUDOS received
Manager
Manager
avatar
S
Joined: 29 May 2016
Posts: 132

Kudos [?]: 17 [1], given: 345

CAT Tests
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 08 Mar 2017, 12:26
1
This post received
KUDOS
Bunuel wrote:
mbaprep2016 wrote:
Bunuel , i have one doubt in this question. i have gone through the explanations in chain, still not clear.

suppose we have been asked in question ...
is |x|=1 ? according to explanations it says x=-1 && x=1 ?
A) x=1 .... so this must be insufficient.

please correct me if I am missing anything.


So, the question is:

Does |x| = 1?

(1) x = 1. This would be sufficient because |1| = 1 and we would have a definite YES answer to the question.

Hope it helps.



I am sorry for asking same question again and again but with similar logic
Question : Is |x| = y - z?

when x > 0 x= y-z && when x<0 x= z-y ??

we have to choose between two values

Now A says x= z-y... this clearly indicates x<0 ...hence sufficient

Kudos [?]: 17 [1], given: 345

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 41891

Kudos [?]: 129095 [0], given: 12194

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 09 Mar 2017, 00:04
mbaprep2016 wrote:
Bunuel wrote:
mbaprep2016 wrote:
Bunuel , i have one doubt in this question. i have gone through the explanations in chain, still not clear.

suppose we have been asked in question ...
is |x|=1 ? according to explanations it says x=-1 && x=1 ?
A) x=1 .... so this must be insufficient.

please correct me if I am missing anything.


So, the question is:

Does |x| = 1?

(1) x = 1. This would be sufficient because |1| = 1 and we would have a definite YES answer to the question.

Hope it helps.



I am sorry for asking same question again and again but with similar logic
Question : Is |x| = y - z?

when x > 0 x= y-z && when x<0 x= z-y ??

we have to choose between two values

Now A says x= z-y... this clearly indicates x<0 ...hence sufficient


OK. Let me demonstrate with number plugging. For (1) if x = 1, and y =2 and z=3, |x| does not equal to y - z.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | 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?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 129095 [0], given: 12194

Intern
Intern
avatar
B
Joined: 30 Dec 2016
Posts: 8

Kudos [?]: 2 [0], given: 140

Location: India
GMAT 1: 670 Q47 V35
GPA: 3.2
GMAT ToolKit User CAT Tests
Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 25 Apr 2017, 23:09
Hi Bunuel, Please point out the error in my approach.

|x|= y - z.
So, when x<0, -x=y-z => x = z - y------(1)
x>0, x = y - z

Statement 1. x = z - y, which is same as (1). So is A not the answer ?

Kudos [?]: 2 [0], given: 140

Manager
Manager
avatar
B
Joined: 31 Dec 2016
Posts: 91

Kudos [?]: 9 [0], given: 22

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 29 Jul 2017, 18:06
Bunuel wrote:
Is \(|x|=y-z\)?

Note that \(y-z\) must be \(\geq{0}\), because absolute value (in our case \(|x|\)) can not be negative.

Generally question asks whether \(y-z\geq{0}\) and whether the difference between them equals to \(|x|\).

(1) \(-x=y-z\)
if \(x>0\) --> \(y-z\) is negative --> no good for us;
if \(x\leq{0}\) --> \(y-z\) is positive --> good.
Two possible answers not sufficient;

(2) \(x<0\)
Not sufficient (we need to know value of y-z is equal or not to |x|)

(1)+(2) Sufficient.

Answer: C.



Just to make this good answer a little clearer. An absolute value cannot equal a negative value. Therefore -x=y-z. as shown in expression 1. If X>0 then we have -5 (because there is a neg sign in front so X = positive 5 but the expression is -5) = y-z. But if Y-z = -5 that means |x| = -5 which is not possible! As said above an absolute value has to equal a positive number. So if X<0 then X could be -5 and - * -5 is positive 5. So y-z = 5 and therefore together we can say that X=Y-Z

Kudos [?]: 9 [0], given: 22

Manager
Manager
avatar
B
Joined: 31 Dec 2016
Posts: 91

Kudos [?]: 9 [0], given: 22

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0 [#permalink]

Show Tags

New post 13 Aug 2017, 18:30
So absolute value we have x = y-z or –x = y-z . That's how you rewrite the ABS value equation. You write one equation with positive X and one with negative to cover both sides.

1) Tells us X+Y=z . It can be arranged into –x=Y-z which matches one of our absolute value formulas. However, if X is positive y-z would be negative and then Y-Z couldn’t equal the absolute value since the ABS value has to equal a non negative numbers.

2) X<0 but we know nothing about Y or Z

3) Combined now we know –(negative number) is positive therefore Y-Z must be positive = Therefore we know |x| = y - z ?

Kudos [?]: 9 [0], given: 22

Re: Is |x| = y - z ? (1) x + y = z (2) x < 0   [#permalink] 13 Aug 2017, 18:30

Go to page   Previous    1   2   3    Next  [ 43 posts ] 

Display posts from previous: Sort by

Is |x| = y - z ? (1) x + y = z (2) x < 0

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.