GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 18 Nov 2018, 13:25

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 in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • How to QUICKLY Solve GMAT Questions - GMAT Club Chat

     November 20, 2018

     November 20, 2018

     09:00 AM PST

     10:00 AM PST

    The reward for signing up with the registration form and attending the chat is: 6 free examPAL quizzes to practice your new skills after the chat.
  • The winning strategy for 700+ on the GMAT

     November 20, 2018

     November 20, 2018

     06:00 PM EST

     07:00 PM EST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.

What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11

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

Hide Tags

Manager
Manager
avatar
Joined: 19 Apr 2010
Posts: 177
Schools: ISB, HEC, Said
What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11  [#permalink]

Show Tags

New post Updated on: 29 Sep 2010, 07:38
2
4
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

54% (01:03) correct 46% (01:26) wrong based on 270 sessions

HideShow timer Statistics

What is the value of y?

(1) 3|x^2 – 4| = y – 2

(2) |3 – y| = 11

Originally posted by prashantbacchewar on 29 Sep 2010, 07:33.
Last edited by prashantbacchewar on 29 Sep 2010, 07:38, edited 1 time in total.
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50627
Re: DS problem  [#permalink]

Show Tags

New post 29 Sep 2010, 07:37
7
What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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) As from (1) \(y\geq{2}\), then \(y=14\). Sufficient.

Answer: C.
_________________

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

General Discussion
Retired Moderator
User avatar
B
Joined: 05 Jul 2006
Posts: 1726
GMAT ToolKit User Premium Member
Re: DS problem 3|x^2 – 4| = y – 2  [#permalink]

Show Tags

New post 29 Sep 2010, 09:14
1
prashantbacchewar wrote:
What is the value of y?

(1) 3|x^2 – 4| = y – 2

(2) |3 – y| = 11


from 1

equation with 2 unknown we can only deduct that y-2> 0 ie: y>2

from 2

y has to have 2 values +ve and -ve..........insuff

both

y>2 , then from 2 y has the +ve value.

C
Retired Moderator
avatar
Joined: 03 Aug 2010
Posts: 210
Re: DS problem  [#permalink]

Show Tags

New post 03 Oct 2010, 15:29
Bunuel wrote:
What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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) As from (1) \(y\geq{2}\), then \(y=14\). Sufficient.

Answer: C.



Hey, pls explain the reasoning of LHS

LHS is absolute value which is never negative, hence RHS als can not be negative.???
_________________

http://www.gmatpill.com/gmat-practice-test/

Amazing Platform

Manager
Manager
User avatar
Joined: 01 Oct 2010
Posts: 67
Re: DS problem  [#permalink]

Show Tags

New post 03 Oct 2010, 15:57
hirendhanak wrote:
Bunuel wrote:
What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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) As from (1) \(y\geq{2}\), then \(y=14\). Sufficient.

Answer: C.



Hey, pls explain the reasoning of LHS

LHS is absolute value which is never negative, hence RHS als can not be negative.???



what values you can put for x?
if you put x = 2, left hand side becomes zero, making y=2.
if you put x as any other value, it will make 3*|x^2 - 4| positive, and add 2 to that, making y > 2.
so, y is either 2 or greater.

Hope this helps.
_________________

Some other posts by me...
My GMAT Journey
Timer Tool for Google spreadsheet
Quant Flash Cards/Pages

700 (Q:49 V:35) - Thanks GMATClub - Test Center experience

Manager
Manager
avatar
Joined: 09 Feb 2011
Posts: 232
Concentration: General Management, Social Entrepreneurship
Schools: HBS '14 (A)
GMAT 1: 770 Q50 V47
Re: Tricky question.  [#permalink]

Show Tags

New post 05 Apr 2011, 21:36
1
1st equation:
x^2 - 4 can be positive, or negative ( say x = 1, then x^2 - 4 is -3, and say x = 3, then x^2-4 is 5. However since its absolute value is taken, it will always be a positive number, which when multiplied by 3 will give either zero (if x=2) or a positive number. This added to 2 brought pver fom RHS of the equation will have to be a positive number still. So while Statement 1 is insufficient in telling us the value of y, it does tell us that y is positive.
Equation 2:
by telling us that absolute value of 3-y is 11 implies that the vlue inside the absolute value lines is either 11 or -11, which means that y is either 14 or -8. since it gives two values of y it is insufficient by itself.
However since statement tells us for certain that y i s positive and statement two give sus two values of y one positive and one negative, both combined we can pick the positive value and be sure that that is the correct value of y
hence both together ae sufficient
Retired Moderator
avatar
B
Joined: 16 Nov 2010
Posts: 1428
Location: United States (IN)
Concentration: Strategy, Technology
Premium Member Reviews Badge
Re: DS problem 3|x^2 – 4| = y – 2  [#permalink]

Show Tags

New post 06 Apr 2011, 03:53
The answer is C. (1) says y is +ve, and (2) gives 2 values of y, one +ve and one -ve. So combining both we get y = 14.
_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Director
Director
avatar
Joined: 01 Feb 2011
Posts: 664
Re: DS problem 3|x^2 – 4| = y – 2  [#permalink]

Show Tags

New post 16 Apr 2011, 16:17
1. Insufficient

because all we know here is y>2

2. Insufficient.

because y can be -8 or 14

together . Sufficient.

Answer is C.
Intern
Intern
avatar
Joined: 21 Mar 2013
Posts: 18
Concentration: Operations, Entrepreneurship
GMAT 1: 620 Q47 V28
GMAT 2: 680 Q45 V38
WE: Engineering (Manufacturing)
Reviews Badge
Re: What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11  [#permalink]

Show Tags

New post 29 Aug 2013, 08:39
What is the value of y?
(1) 3|x^2 – 4| = y – 2
(2) |3 – y| = 11

Stmt 1: Y=3|x^2-4|+2. The value of y will change with the value of x. insufficient.
Stmt2: 3-y=11 OR 3-y=-11. We get y=-8 in first case and y=14 in second. Insufficient.
Together: Anything inside a Modulus is ALWAYS positive. Therefore, |x^2-4| will always positive. And when we add 2 to it, the result still remains positive. That means, y cannot be -8 from stmt2. Sufficient. Answer C.
Manager
Manager
avatar
Joined: 07 Apr 2012
Posts: 100
Location: United States
Concentration: Entrepreneurship, Operations
Schools: ISB '15
GMAT 1: 590 Q48 V23
GPA: 3.9
WE: Operations (Manufacturing)
Re: DS problem  [#permalink]

Show Tags

New post 07 Sep 2013, 23:55
[quote="Bunuel"]What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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."

Bunuel,

In this case we said since the LHS has a mod so its value is positive always. But we also know mod function is negative for values of x < 0 , or we dont always assume for a given equation say |x-2| =2 , that LHS is positive always ? we say x-2 = x-2 , when x> 2 and 2-x when x < 2.
So this looks a contradiction, can you please explain ?
Manager
Manager
avatar
Status: Persevering
Joined: 15 May 2013
Posts: 170
Location: India
Concentration: Technology, Leadership
GMAT Date: 08-02-2013
GPA: 3.7
WE: Consulting (Consulting)
GMAT ToolKit User
Re: DS problem  [#permalink]

Show Tags

New post 08 Sep 2013, 04:01
ygdrasil24 wrote:
Bunuel wrote:
What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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."

Bunuel,

In this case we said since the LHS has a mod so its value is positive always. But we also know mod function is negative for values of x < 0 , or we dont always assume for a given equation say |x-2| =2 , that LHS is positive always ? we say x-2 = x-2 , when x> 2 and 2-x when x < 2.
So this looks a contradiction, can you please explain ?


In this case for statement 1,

as it is in modulus so LHS will always be positive, its x whose value can be -ve or +ve, but LHS will always be +ve.
Therefore we conclude that y-2>=0 or y>=2

From statement 2 we get y=-8,14

Combining 1 and 2, we get y=14

Hope it is clear.
_________________

--It's one thing to get defeated, but another to accept it.

Manager
Manager
avatar
Joined: 07 Apr 2012
Posts: 100
Location: United States
Concentration: Entrepreneurship, Operations
Schools: ISB '15
GMAT 1: 590 Q48 V23
GPA: 3.9
WE: Operations (Manufacturing)
Re: DS problem  [#permalink]

Show Tags

New post 08 Sep 2013, 04:23
In this case for statement 1,

as it is in modulus so LHS will always be positive, its x whose value can be -ve or +ve, but LHS will always be +ve.
Therefore we conclude that y-2>=0 or y>=2

From statement 2 we get y=-8,14

Combining 1 and 2, we get y=14

Hope it is clear.[/quote]

Let us take an example. y =|X-2|
So y = x-2 , when x-2>0 or x-2=0
and y = 2-x, when x-2<0 ro x <2

If we take x = 3, then y = -1, how ? I am doing something silly here for sure!
If you see graph of mod function Y is always positive, so how is Y = -1 above at x =3 ?
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50627
Re: DS problem  [#permalink]

Show Tags

New post 08 Sep 2013, 04:33
ygdrasil24 wrote:
Bunuel wrote:
What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

(1) As 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."

Bunuel,

In this case we said since the LHS has a mod so its value is positive always. But we also know mod function is negative for values of x < 0 , or we dont always assume for a given equation say |x-2| =2 , that LHS is positive always ? we say x-2 = x-2 , when x> 2 and 2-x when x < 2.
So this looks a contradiction, can you please explain ?


It seems that you should brush up your fundamentals.

First of all: absolute value is always greater than or equal to zero (\(\geq{0}\)), not \(>0\).

Next, |x|=-x, when x<0 --> \(|x|=-x=-negative=positive\).

Theory on Abolute Values: math-absolute-value-modulus-86462.html

DS Abolute Values Questions to practice: search.php?search_id=tag&tag_id=37
PS Abolute Values Questions to practice: search.php?search_id=tag&tag_id=58

Hard set on Abolute Values: inequality-and-absolute-value-questions-from-my-collection-86939.html

_________________

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

Manager
Manager
avatar
Joined: 07 Apr 2012
Posts: 100
Location: United States
Concentration: Entrepreneurship, Operations
Schools: ISB '15
GMAT 1: 590 Q48 V23
GPA: 3.9
WE: Operations (Manufacturing)
Re: DS problem  [#permalink]

Show Tags

New post 08 Sep 2013, 04:38
Ok Thanks. I was missing this - of -x = +x, So basically in mod function x can range from - to +, but y will always be >0 or = 0. Correct me if I understood it wrongly.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50627
Re: DS problem  [#permalink]

Show Tags

New post 08 Sep 2013, 04:40
ygdrasil24 wrote:
Ok Thanks. I was missing this - of -x = +x, So basically in mod function x can range from - to +, but y will always be >0 or = 0. Correct me if I understood it wrongly.


Apart from the red part all is correct. The red part does not make sense.
_________________

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

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8816
Premium Member
Re: What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11  [#permalink]

Show Tags

New post 22 Oct 2018, 07:25
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

GMAT Club Bot
Re: What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11 &nbs [#permalink] 22 Oct 2018, 07:25
Display posts from previous: Sort by

What is the value of y? (1) 3|x^2 4| = y 2 (2) |3 y| = 11

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.