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

It is currently 22 Jul 2018, 09:41

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

What is the value of y?

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

Hide Tags

Manager
Manager
avatar
Joined: 20 Mar 2015
Posts: 62
GMAT ToolKit User
Re: What is the value of y?  [#permalink]

Show Tags

New post 06 May 2016, 21:47
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 cannot 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.


Why is Y>=0? Can't we write 'Y>0'? If LHS is positive and RHS must also be positive then, RHS has to be greater than 0. As 0 is neither positive nor negative, how can we write Y>=0?

|some value|= some value. Since LHS is an absolute value, RHS has to be positive as well. Why is RHS>=0 and not RHS>0?
Expert Post
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6280
Re: What is the value of y?  [#permalink]

Show Tags

New post 06 May 2016, 22:12
shekhar4847 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 cannot 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.


what if y is between 2 and 3?
In that case we will have two values of y.
Could you please clarify?


Hi shekhar4847,

I gives you \(y\geq{2}\)...
II gives you two cases..
a) \(y<3\) --> \(3-y=11\) --> \(y=-8\);
this means if y<3, it can have ONLY -8 as the value,
so when we combine this with \(y\geq{2}\),which does not fit between 2 and 3.. hence WRONG

b)\(y\geq{3}\) --> \(-3+y=11\) --> \(y=14\)
this means if \(y\geq{3}\), it can have ONLY 14 as the value,
so when we combine this with \(y\geq{2}\), 14 fits in both the ranges.. hence CORRECT
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Expert Post
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6280
Re: What is the value of y?  [#permalink]

Show Tags

New post 06 May 2016, 22:15
bimalr9 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 cannot 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.


Why is Y>=0? Can't we write 'Y>0'? If LHS is positive and RHS must also be positive then, RHS has to be greater than 0. As 0 is neither positive nor negative, how can we write Y>=0?

|some value|= some value. Since LHS is an absolute value, RHS has to be positive as well. Why is RHS>=0 and not RHS>0?


Hi,
an ABSOLUTE value is NOT necessarily positive, it is NON-NEGATIVE, so it can include both 0 and +ive value..
if in statement I x is 2 or -2, LHS will be 0 and hence y=2..
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Moderator
avatar
V
Joined: 22 Jun 2014
Posts: 1053
Location: India
Concentration: General Management, Technology
GMAT 1: 540 Q45 V20
GPA: 2.49
WE: Information Technology (Computer Software)
GMAT ToolKit User Premium Member
Re: What is the value of y?  [#permalink]

Show Tags

New post 07 May 2016, 01:49
dvinoth86 wrote:
What is the value of y?


(1) 3|x^2 – 4| = y – 2
(2) |3 – y| = 11

Y = ?

stmt:1 - it has two variables X AND Y. we need value of Y. insuff.

stmt:2 - Y=-8 or Y=11 insuff.

combined: -

frm stmt-1 3|x^2 – 4| = y – 2

X^2 is positive. value of mod is positive. so left hand side is POSITIVE.

frm stmt-2 Y=-8 or Y=11

so we can only pick 11 as the value to keep right hand side POSITIVE.

Option C is right.
_________________

---------------------------------------------------------------
Target - 720-740
http://gmatclub.com/forum/information-on-new-gmat-esr-report-beta-221111.html
http://gmatclub.com/forum/list-of-one-year-full-time-mba-programs-222103.html

Intern
Intern
avatar
Joined: 11 Sep 2015
Posts: 7
What is the value of y?  [#permalink]

Show Tags

New post 14 Aug 2016, 01:44
Hi Bunuel,

Please correct me if i am wrong.

i). 3|x^2 - 4| =y-2

3x^2 = y+ 10 OR 3x^2 = -y +14
equating the 2 values of 3x^2 Cant we equate these 2 values?
y=10 = -y +14
y=2


ii). gives 2 values of y -8 & 14

therefore, answer is A
Board of Directors
User avatar
V
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3687
Premium Member Reviews Badge CAT Tests
Re: What is the value of y?  [#permalink]

Show Tags

New post 14 Aug 2016, 02:39
shrashtisinghal wrote:
Hi Bunuel,

Please correct me if i am wrong.

i). 3|x^2 - 4| =y-2

3x^2 = y+ 10 OR 3x^2 = -y +14
equating the 2 values of 3x^2 Cant we equate these 2 values?
y=10 = -y +14
y=2


ii). gives 2 values of y -8 & 14

therefore, answer is A


How do you know that we have

3x^2 - 12 =y-2

or

12 - 3x^2 =y-2

Since, we donot know which of the above equations is valid. We cannot deduce a single value.

As per Modulus property,

Mod(x) = x if x>0
= -x if x<0.

Hence A is not sufficient.

In B also, we are getting two values of y, so not sufficient.

But, when you combine the statements, you will see the equation is satisfied only for y =14. hence, C.
_________________

My GMAT Story: From V21 to V40
My MBA Journey: My 10 years long MBA Dream
My Secret Hacks: Best way to use GMATClub | Importance of an Error Log!
Verbal Resources: All SC Resources at one place | All CR Resources at one place
Blog: Subscribe to Question of the Day Blog

GMAT Club Inbuilt Error Log Functionality - View More.
New Visa Forum - Ask all your Visa Related Questions - here.

New! Best Reply Functionality on GMAT Club!



Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for free

Retired Moderator
User avatar
B
Joined: 05 Jul 2006
Posts: 1734
GMAT ToolKit User Premium Member
Re: What is the value of y?  [#permalink]

Show Tags

New post 18 Oct 2016, 00:52
dvinoth86 wrote:
What is the value of y?

(1) 3|x^2 – 4| = y – 2
(2) |3 – y| = 11


FROM 1
(y-2)/3 >= 0 , thus y>= 2 ... ... insuff

from 2

3-y = 11 or 3-y = -11 , thus Y could be either -8 or 14.. insuff

both together

since from 1 y>= 2 and from 2 y = -8 or 14 then y = 4 ( common domain) ...C
Intern
Intern
avatar
B
Joined: 26 Feb 2015
Posts: 31
Location: Thailand
Concentration: Entrepreneurship, Strategy
GMAT 1: 630 Q49 V27
GMAT 2: 680 Q48 V34
GPA: 2.92
WE: Supply Chain Management (Manufacturing)
Re: What is the value of y?  [#permalink]

Show Tags

New post 14 Aug 2017, 21:32
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 cannot 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.



Brilliant approach! I'd never thought it could be this easy.
Manager
Manager
User avatar
B
Joined: 21 Jul 2017
Posts: 139
Location: India
Concentration: Social Entrepreneurship, Leadership
GMAT 1: 650 Q47 V33
GPA: 4
WE: Project Management (Education)
CAT Tests
Re: What is the value of y?  [#permalink]

Show Tags

New post 22 Sep 2017, 10:22
Re: What is the value of y? &nbs [#permalink] 22 Sep 2017, 10:22

Go to page   Previous    1   2   3   [ 49 posts ] 

Display posts from previous: Sort by

What is the value of y?

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

Events & Promotions

PREV
NEXT


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®.