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

It is currently 18 Jan 2019, 18:18

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 January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
  • FREE Quant Workshop by e-GMAT!

     January 20, 2019

     January 20, 2019

     07:00 AM PST

     07:00 AM PST

    Get personalized insights on how to achieve your Target Quant Score.

If the operation @ is defined for all a and b by the equatio

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

Hide Tags

 
Intern
Intern
avatar
Joined: 17 Sep 2003
Posts: 3
Location: NY
If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post Updated on: 11 Aug 2014, 23:58
2
6
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

81% (01:00) correct 19% (01:16) wrong based on 360 sessions

HideShow timer Statistics

If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4

Originally posted by pete300 on 18 Sep 2003, 06:58.
Last edited by Bunuel on 11 Aug 2014, 23:58, edited 1 time in total.
Renamed the topic, edited the question, added the OA and moved to PS forum.
Manager
Manager
avatar
Joined: 15 Sep 2003
Posts: 70
Location: california
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 21 Sep 2003, 10:37
2
1
Formula: a@b=((a^2)*b)/3
Question: 2@(3@-1)= ?

work within the parenthesis first so solve (3@-1) first


(3@-1)= ((3^2)*-1)/3 = (9*-1)/3= -9/3=-3
now take -3 plug back into equation and solve the rest

2@(-3)=((2^2)*-3)/3 = (4*-3)/3= -12/3= -4

so -4 is the answer....this question is merely testing order of operations

remember PEMDAS
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52285
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 00:03
pete300 wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


Check other Operations/functions defining algebraic/arithmetic expressions probelms in our Special Questions Directory.
_________________

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

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1823
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 00:09
pete300 wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


Hi Bunuel,

Kindly write this equation in mathematical format. It's impossible to understand otherwise :)

Thanks
_________________

Kindly press "+1 Kudos" to appreciate :)

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52285
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 01:29
PareshGmat wrote:
pete300 wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


Hi Bunuel,

Kindly write this equation in mathematical format. It's impossible to understand otherwise :)

Thanks


There is nothing wrong with the format.
_________________

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

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1823
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 02:05
Bunuel wrote:
PareshGmat wrote:
pete300 wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


Hi Bunuel,

Kindly write this equation in mathematical format. It's impossible to understand otherwise :)

Thanks


There is nothing wrong with the format.


a@b =(a^2*b)/3

Is it \(\frac{a^{2b}}{3}\) or

\(\frac{ba^2}{3}\) ??
_________________

Kindly press "+1 Kudos" to appreciate :)

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52285
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 02:12
PareshGmat wrote:
Bunuel wrote:
PareshGmat wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4

Hi Bunuel,

Kindly write this equation in mathematical format. It's impossible to understand otherwise :)

Thanks


There is nothing wrong with the format.


a@b =(a^2*b)/3

Is it \(\frac{a^{2b}}{3}\) or

\(\frac{ba^2}{3}\) ??


If it were \(\frac{a^{2b}}{3}\), then it would be written as (a^(2*b))/3.
_________________

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

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1823
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Aug 2014, 02:27
1
a@b \(= \frac{ba^2}{3}\)

2@(3@-1)

Solving the bracket first

3@-1\(= \frac{-1*3^2}{3} = -3\)

2@-3\(= \frac{-3*2^2}{3} = -4\)

Answer = E
_________________

Kindly press "+1 Kudos" to appreciate :)

Manager
Manager
User avatar
Joined: 04 Aug 2013
Posts: 96
Location: India
Schools: McCombs '17
GMAT 1: 670 Q47 V35
GPA: 3
WE: Manufacturing and Production (Pharmaceuticals and Biotech)
If the operation ◙ is defined for all a and b by the equation a ◙ b =  [#permalink]

Show Tags

New post 16 Mar 2016, 17:55
If the operation ◙ is defined for all a and b by the equation a ◙ b = \(a^2b\)/3
then 2 ◙ (3 ◙ – 1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4
Intern
Intern
avatar
Joined: 10 Nov 2014
Posts: 8
Re: If the operation ◙ is defined for all a and b by the equation a ◙ b =  [#permalink]

Show Tags

New post 16 Mar 2016, 18:07
anceer wrote:
If the operation ◙ is defined for all a and b by the equation a ◙ b = \(a^2b\)/3
then 2 ◙ (3 ◙ – 1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


Just plugging numbers into the function and following through.

First, we solve for (3 ◙ – 1).

\(((3^2)(-1)) / 3 = -3\)

Now we solve for 2 ◙ -3

\(((2^2)(-3)) / 3 = -4\)

Answer is -4 (E)
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52285
Re: If the operation is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 16 Mar 2016, 21:06
Intern
Intern
avatar
B
Joined: 01 Sep 2016
Posts: 8
Re: If the operation is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 12 Sep 2016, 13:13
I agree that the way the equation is written is kind of confusing...
Director
Director
User avatar
D
Joined: 04 Dec 2015
Posts: 738
Location: India
Concentration: Technology, Strategy
Schools: ISB '19, IIMA , IIMB, XLRI
WE: Information Technology (Consulting)
GMAT ToolKit User
Re: If the operation @ is defined for all a and b by the equatio  [#permalink]

Show Tags

New post 22 Dec 2018, 18:44
pete300 wrote:
If the operation @ is defined for all a and b by the equation a@b =(a^2*b)/3, then 2@(3@-1) =

A. 4
B. 2
C. -4/3
D. -2
E. -4


\(a@b =\frac{(a^2*b)}{3}\)

\(2@(3@-1)\) ----- \((i)\)

\(3@-1 = \frac{3^2*(-1)}{3} = \frac{-9}{3} = -3\)

Hence \((i)\) becomes \(=> 2@-3\)

\(2@-3 = \frac{2^2*-3}{3} = -4\)

Answer E
GMAT Club Bot
Re: If the operation @ is defined for all a and b by the equatio &nbs [#permalink] 22 Dec 2018, 18:44
Display posts from previous: Sort by

If the operation @ is defined for all a and b by the equatio

  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®.