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

It is currently 17 Jan 2019, 05:06

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
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • 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.

M26-36

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

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52228
M26-36  [#permalink]

Show Tags

New post 16 Sep 2014, 00:26
1
11
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

32% (01:02) correct 68% (01:15) wrong based on 225 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52228
Re M26-36  [#permalink]

Show Tags

New post 16 Sep 2014, 00:26
3
2
Official Solution:


(1) \(xyz=-6\). Infinitely many combinations of \(x\), \(y\) and \(z\) are possible which will give different values of the expression in the stem: try \(x=y=1\) and \(y=-6\) or \(x=1\), \(y=2\), \(z=-3\). Not sufficient.

(2) \(x+y+z=0\). Rearrange: \(x=-(y+z)\) and substitute this value of \(x\) into the expression in the stem to get \(\frac{x^3+y^3+z^3}{xyz}=\frac{-(y+z)^3+y^3+z^3}{xyz}=\frac{-y^3-3y^2z-3yz^2-z^3+y^3+z^3}{xyz}=\frac{-3y^2z-3yz^2}{xyz}=\frac{-3yz(y+z)}{xyz}\), as \(x=-(y+z)\) then:

\(\frac{-3yz(y+z)}{xyz}=\frac{-3yz*(-x)}{xyz}=\frac{3xyz}{xyz}=3\). Sufficient.

Must know for the GMAT:\((x+y)^3=(x+y)(x^2+2xy+y^2)=x^3+3x^2y+3xy^2+y^3\) and \((x-y)^3=(x-y)(x^2-2xy+y^2)=x^3-3x^2y+3xy^2-y^3\).


Answer: B
_________________

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

Intern
Intern
User avatar
Joined: 16 Jul 2014
Posts: 35
Premium Member
Re: M26-36  [#permalink]

Show Tags

New post 04 Nov 2014, 17:21
1
Once it gets to this stage:

−3yz(y+z)
xyz

yz can be canceled out so we're only left with:

−3(y+z)
x

And since x = -(y+z)

3x
x

= 3
Manager
Manager
avatar
P
Joined: 17 May 2017
Posts: 130
GPA: 3
Reviews Badge
Re: M26-36  [#permalink]

Show Tags

New post 30 Aug 2017, 00:43
1
Can I expect such type of questions in GMAT
this is more or less like CAT(Entrance Exam for Indian Institute of Management) Question
Manager
Manager
avatar
G
Joined: 20 Feb 2017
Posts: 164
Location: India
Concentration: Operations, Strategy
WE: Engineering (Other)
Re: M26-36  [#permalink]

Show Tags

New post 17 Dec 2017, 12:29
3
1
THERE IS A SIMPLE PROPERTY
IF X+Y+Z = 0
THEN X^3+Y^3+Z^3 = 3XYZ
HOPE IT HELPS
_________________

If you feel the post helped you then do send me the kudos (damn theya re more valuable than $)

Manager
Manager
avatar
G
Joined: 30 May 2017
Posts: 135
Location: United States
Schools: HBS '21
GMAT 1: 690 Q50 V32
GRE 1: Q168 V164
GPA: 3.57
CAT Tests
M26-36  [#permalink]

Show Tags

New post 05 May 2018, 17:46
THERE IS A SIMPLE PROPERTY
IF X+Y+Z = 0
THEN X^3+Y^3+Z^3 = 3XYZ
HOPE IT HELPS

I assume we only expect the property above when NONE of X,Y and Z is equal to zero.
_________________

Kindly press the +1Kudos if you like the explanation. Thanks a lot!!!

Senior Manager
Senior Manager
User avatar
S
Joined: 08 Jun 2015
Posts: 432
Location: India
GMAT 1: 640 Q48 V29
GMAT 2: 700 Q48 V38
GPA: 3.33
Premium Member Reviews Badge
Re: M26-36  [#permalink]

Show Tags

New post 24 Jul 2018, 05:19
Use the property -> x^3+y^3+z^3 - 3xyz=(x+y+z)*(x^2+y^2+z^2-xy-yz-zx) . If x+y+z=0 , The required expression comes to 3. I doubt though if such a formulaic question will ever come on the GMAT !!!
_________________

" The few , the fearless "

Manager
Manager
User avatar
S
Joined: 20 Jul 2018
Posts: 89
GPA: 2.87
Re: M26-36  [#permalink]

Show Tags

New post 05 Sep 2018, 08:23
statement 1 not sufficient as many combinations of x,y and z are possible which can result into different values.
statement 2 implies:
\(x+y+z=0\)
\(x=-(y+z)\)
substitute for x
\(\frac{(-y^3 - z^3 - 3y^2z -3yz^z +y^3 + z^3)}{xyz}\)
\(\frac{-3yz(y+z)}{xyz}\)
\(\frac{-3yz(y+z)}{-yz(y+z)}\)
\(3\)
Sufficient

Answer is B
_________________

Hasnain Afzal

"When you wanna succeed as bad as you wanna breathe, then you will be successful." -Eric Thomas

Intern
Intern
avatar
B
Joined: 31 Jul 2017
Posts: 19
Re: M26-36  [#permalink]

Show Tags

New post 06 Sep 2018, 20:05
Any OG/GMAT question which employs (x+y)^3 formula in its solution?
Manager
Manager
avatar
B
Joined: 26 Sep 2018
Posts: 57
Location: Sweden
CAT Tests
Re: M26-36  [#permalink]

Show Tags

New post 11 Jan 2019, 11:20
Bunnel you are some legend
GMAT Club Bot
Re: M26-36 &nbs [#permalink] 11 Jan 2019, 11:20
Display posts from previous: Sort by

M26-36

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

Moderators: chetan2u, Bunuel



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®.