|
Author |
Message |
|
TAGS:
|
|
|
Manager
Joined: 19 Oct 2011
Posts: 136
Location: India
Followers: 2
Kudos [?]:
87
[7] , given: 33
|
What is the value of y? [#permalink]
 22 Feb 2012, 19:51
7
This post received
KUDOS
Question Stats:
43% (02:07) correct
56% (01:08) wrong based on 20 sessions
What is the value of y? (1) 3|x^2 – 4| = y – 2 (2) |3 – y| = 11
_________________
Encourage me by pressing the KUDOS if you find my post to be helpful. Help me win "The One Thing You Wish You Knew - GMAT Club Contest"the-one-thing-you-wish-you-knew-gmat-club-contest-140358.html#p1130989
|
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11628
Followers: 1802
Kudos [?]:
9613
[12] , given: 829
|
Re: What is the value of y? [#permalink]
22 Feb 2012, 21:50
12
This post received
KUDOS
|
|
|
|
|
|
Manager
Joined: 14 Feb 2012
Posts: 226
Followers: 1
Kudos [?]:
6
[1] , given: 7
|
Re: What is the value of y? (1) 3|x2 – 4| = y – 2 (2) |3–y|=11 [#permalink]
23 Apr 2012, 22:33
1
This post received
KUDOS
C for sure is the answer , Bunuel your explanations are simply awsome. Thanks
_________________
The Best Way to Keep me ON is to give Me KUDOS !!!
If you Like My posts please Consider giving Kudos
Shikhar
|
|
|
|
|
|
Manager
Joined: 16 Mar 2010
Posts: 59
Followers: 0
Kudos [?]:
4
[0], given: 4
|
Re: What is the value of y? (1) 3|x2 – 4| = y – 2 (2) |3–y|=11 [#permalink]
28 Apr 2012, 11:01
Answer C, Bunuel's explaination has definitely helped me better understand absolute value questions.
|
|
|
|
|
|
SVP
Joined: 01 Sep 2010
Posts: 1747
Followers: 56
Kudos [?]:
585
[0], given: 467
|
Re: What is the value of y? [#permalink]
05 Jul 2012, 11:52
Bunuel wrote: What is the value of y?
(1) 3|x^2-4|=y-2. Now, since we are asked to find the value of y, from this statement we can conclude only that y\geq{2}, as LHS is absolute value which is never negative, hence RHS als can not be negative. Not sufficient.
(2) |3 - y| = 11:
y<3 --> 3-y=11 --> y=-8;
y\geq{3} --> -3+y=11 --> y=14.
Two values for y. Not sufficient.
(1)+(2) Since from (1) y\geq{2}, then from (2) y=14. Sufficient.
Answer: C.
Hope it's clear. Sorry I can't to figure out why y >= 2........ 1) 3x^2 - 4 = y-2 and -3x^2 + 4 = y-2 and then ??'  thanks
_________________
KUDOS is the good manner to help the entire community.
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11628
Followers: 1802
Kudos [?]:
9613
[1] , given: 829
|
Re: What is the value of y? [#permalink]
05 Jul 2012, 11:57
1
This post received
KUDOS
carcass wrote: Bunuel wrote: What is the value of y?
(1) 3|x^2-4|=y-2. Now, since we are asked to find the value of y, from this statement we can conclude only that y\geq{2}, as LHS is absolute value which is never negative, hence RHS als can not be negative. Not sufficient.
(2) |3 - y| = 11:
y<3 --> 3-y=11 --> y=-8;
y\geq{3} --> -3+y=11 --> y=14.
Two values for y. Not sufficient.
(1)+(2) Since from (1) y\geq{2}, then from (2) y=14. Sufficient.
Answer: C.
Hope it's clear. Sorry I can't to figure out why y >= 2........ 1) 3x^2 - 4 = y-2 and -3x^2 + 4 = y-2 and then ??' thanks We are given that 3|x^2-4|=y-2. Now, the left hand side in this expression ( 3|x^2-4|) is an absolute value, so it cannot be negative, so the right hand side of the expression ( y-2) must also be non-negative: y-2\geq{0} --> y\geq{2}. Hope it's clear.
_________________
PLEASE READ AND FOLLOW: 11 Rules for Posting!!!
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory
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. NEW!!!
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. NEW!!!
What are GMAT Club Tests?
25 extra-hard Quant Tests
Find out what's new at GMAT Club - latest features and updates
|
|
|
|
|
|
Director
Status: Final Lap Up!!!
Affiliations: NYK Line
Joined: 21 Sep 2012
Posts: 943
Location: India
GMAT Date: 05-29-2013
GPA: 3.2
WE: Engineering (Transportation)
Followers: 13
Kudos [?]:
91
[0], given: 57
|
Re: What is the value of y? [#permalink]
03 Oct 2012, 20:05
pls point out if i am wrong
1.
3(x^2- 4) = y- 2
and 3(x^2-4)= - (y-2)
y=-4
y=-16
from 2
y = 8
y= 14
so e is the answer
|
|
|
|
|
|
Director
Joined: 22 Mar 2011
Posts: 608
WE: Science (Education)
Followers: 43
Kudos [?]:
267
[0], given: 43
|
Re: What is the value of y? [#permalink]
04 Oct 2012, 01:29
Archit143 wrote: pls point out if i am wrong
1.
3(x^2- 4) = y- 2
and 3(x^2-4)= - (y-2)
y=-4
y=-16
from 2
y = 8
y= 14
so e is the answer from 2 y = 8 - should be y = -8; |3-8| = |-5| = 5 and not 11; |3-(-8)| = |3+8| = 11 y= 14 3(x^2- 4) = y-2 it should be 3|x^2-4|=y-2 if y-2\geq0.
and 3(x^2-4)= -(y-2) it should be 3|x^2-4|=-(y-2) if y-2<0
but we don't have any information about y.
y=-4
y=-16 No justification for these values, we don't know what is the value of x.Statement (1) is not sufficient. Statement (2) provides two possible values for y, not sufficient. Taken together (1) and (2): since y-2 equals an absolute value, it should be non-negative. Only y = 14 is acceptable. Sufficient, therefore answer C.
_________________
PhD in Applied Mathematics
Love GMAT Quant questions and running.
|
|
|
|
|
|
Director
Joined: 02 Jul 2012
Posts: 769
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 19
Kudos [?]:
260
[0], given: 45
|
Re: What is the value of y? [#permalink]
20 Oct 2012, 13:01
nitzz wrote: What is the value of y?
(1) 3|x2 – 4| = y – 2
(2) |3 – y| = 11 1) x can be any number and hence we can substitute any number of x and get various values for y. Insufficient 2) y can either be 14 or -8. Insufficient 1 & 2 together. | x2 – 4| should be positive since modulus cannot take negative values. So \frac{y-2}{3} should be positive. So y is 14. Answer is C
_________________
Kudos Please... If my post helped.
Thanks To The Almighty - My GMAT Debrief
My Own CR Question 1|My Own CR Question 2|My Own DS Question 1|My Own DS Question 2|
My Own PS Question 1
|
|
|
|
|
|
SVP
Joined: 01 Sep 2010
Posts: 1747
Followers: 56
Kudos [?]:
585
[0], given: 467
|
Re: What is the value of y? [#permalink]
20 Oct 2012, 15:38
I'm not completely sure about your explanation though I have obtained C like answer If someone can explain this question better, go ahead 
_________________
KUDOS is the good manner to help the entire community.
|
|
|
|
|
|
Director
Joined: 02 Jul 2012
Posts: 769
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 19
Kudos [?]:
260
[0], given: 45
|
Re: What is the value of y? [#permalink]
20 Oct 2012, 23:58
carcass wrote: I'm not completely sure about your explanation though I have obtained C like answer If someone can explain this question better, go ahead If you could tell me what is worrying about my explanation, I would be pleased to clear it up.
_________________
Kudos Please... If my post helped.
Thanks To The Almighty - My GMAT Debrief
My Own CR Question 1|My Own CR Question 2|My Own DS Question 1|My Own DS Question 2|
My Own PS Question 1
|
|
|
|
|
|
Intern
Joined: 28 Aug 2012
Posts: 47
Concentration: Operations, Marketing
GMAT 1: 510 Q36 V25
GPA: 4
WE: Information Technology (Other)
Followers: 0
Kudos [?]:
23
[0], given: 99
|
Re: What is the value of y? [#permalink]
06 Apr 2013, 11:35
Bunuel,
I understand from statement 1 we get y>=2 , but when we combine both statements together we get y>=2 and y=14. Now how can we just assume y to be 14, because y can also take the value of 2 right .
I chose E on this basis .
Thanks
TT
|
|
|
|
|
|
Director
Joined: 02 Sep 2012
Posts: 575
Location: Italy
Concentration: Finance, Entrepreneurship
GMAT Date: 08-02-2013
GPA: 3.8
Followers: 20
Kudos [?]:
346
[1] , given: 79
|
Re: What is the value of y? [#permalink]
06 Apr 2013, 15:11
1
This post received
KUDOS
thinktank wrote: Bunuel,
I understand from statement 1 we get y>=2 , but when we combine both statements together we get y>=2 and y=14. Now how can we just assume y to be 14, because y can also take the value of 2 right .
I chose E on this basis .
Thanks
TT That's not correct. Y cannot be 2, otherwise the second equation would not be true. |3-2|=11, 1=11 As you can see if we pick 2, the second equation is not verified. If take a look at the explanations above, you'll find out that statement 2 defines two possible vaules for y (-8,14)[ not enough to say the value of y]; and that statement 1 is true only for y>=2, because 3|x^2-4|=y-2, the left part is always >=0 (thanks to the abs value), and so the right part must be >=0 too. If we merge those conditions: y=-8 or y=14 with y>=2, the only value that y can have is 14 Hope it's clear now
_________________
Experience without theory is blind, but theory without experience is mere intellectual play.
Immanuel Kant , General Systems
First rule about GMATClub : you do not talk about GMATClub 
Second rule about GMATClub : a great post deserves a +1 KUDOS
Tips and tricks: Inequalities , Mixture | Review: MGMAT workshop
Strategy: SmartGMAT v1.0 | Questions: Verbal challenge SC CR New CR is out! SC coming soon , My Quant
|
|
|
|
|
|
Manager
Joined: 21 Jul 2012
Posts: 61
Followers: 0
Kudos [?]:
6
[0], given: 32
|
Re: What is the value of y? [#permalink]
28 Apr 2013, 15:17
I know this is not needed for this problem but can someone show me how to solve 3|x^2 - 4| = y-2 from statement 1? Like what are the equations you could form if you tried to isolate y in this example?
|
|
|
|
|
|
Senior Manager
Joined: 10 Oct 2012
Posts: 287
Followers: 4
Kudos [?]:
94
[0], given: 20
|
Re: What is the value of y? [#permalink]
29 Apr 2013, 02:08
jmuduke08 wrote: I know this is not needed for this problem but can someone show me how to solve 3|x^2 - 4| = y-2 from statement 1? Like what are the equations you could form if you tried to isolate y in this example? We have y = 2+3|x^2-4|Case I: x>2 --> We can remove the modulus sign as it is and y = 2+3(x^2-4) = 3x^2-10Case II : -2<x<2 --> y = 2+3(4-x^2) = 14-3x^2Case III : x<-2 Just as in Case I; y = 3x^2-10For x=2 or x=-2, y = 2.
|
|
|
|
|
|
Manager
Status: Pushing Hard
Affiliations: GNGO2, SSCRB
Joined: 30 Sep 2012
Posts: 98
Location: India
Concentration: Finance, Entrepreneurship
GPA: 3.33
WE: Analyst (Health Care)
Followers: 1
Kudos [?]:
35
[0], given: 11
|
DS Absolute value equation: What is the value of y? [#permalink]
29 Apr 2013, 12:00
What is the value of y? (1) 3|x^2 – 4| = y – 2 (2) |3 – y| = 11
_________________
If you don’t make mistakes, you’re not working hard. And Now that’s a Huge mistake.
Please Press..... Kudos ++... If my Post helped.....................
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11628
Followers: 1802
Kudos [?]:
9613
[0], given: 829
|
Re: DS Absolute value equation: What is the value of y? [#permalink]
29 Apr 2013, 12:56
|
|
|
|
|
|
|
Re: DS Absolute value equation: What is the value of y?
[#permalink]
29 Apr 2013, 12:56
|
|
|
|
|
|
|
|
|
|
|
close
