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

It is currently 21 Jan 2019, 03:55

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
  • GMAT Club Tests are Free & Open for Martin Luther King Jr.'s Birthday!

     January 21, 2019

     January 21, 2019

     10:00 PM PST

     11:00 PM PST

    Mark your calendars - All GMAT Club Tests are free and open January 21st for celebrate Martin Luther King Jr.'s Birthday.
  • The winners of the GMAT game show

     January 22, 2019

     January 22, 2019

     10:00 PM PST

     11:00 PM PST

    In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one.

What is the value of x^3?

  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: 52337
What is the value of x^3?  [#permalink]

Show Tags

New post 17 Feb 2016, 02:33
1
3
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

91% (00:30) correct 9% (00:35) wrong based on 438 sessions

HideShow timer Statistics

VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 17 Feb 2016, 09:50
4
Bunuel wrote:
What is the value of x^3?

(1) |x|=2
(2) 5x+6=16

Kudos for correct solution.



(1) IXI=2
x=2,-2
so X^3=8,-8
not sufff..
(2) 5X+6=16

x=2
so X^3=8 suff.
Ans B
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6823
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 17 Feb 2016, 22:08
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

What is the value of x^3?

(1) |x|=2
(2) 5x+6=16


In the original condition, there is 1 variable(x), which should match with the number of equations. So you need 1 equation. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
For 1), x^3=-8,8 is derived from x=-2,2, which is not unique and not sufficient.
For 2), 5x=10, x=3, x^3=8 is derived, which is unique and sufficient.
Therefore, the answer is B.


 For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Current Student
avatar
B
Joined: 07 Mar 2015
Posts: 110
Location: India
Concentration: General Management, Operations
GMAT 1: 590 Q46 V25
GPA: 3.84
WE: Engineering (Energy and Utilities)
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 17 Feb 2016, 22:38
1
Here the concept tested is one property of even and odd powers
Even powers will result in a +ve sign always
ODD powers will have the same sign of the variable. So for ODD powers it is must to know the sign of variable
S1 : +2 or -2 ( sign not fixed)
S2 = sign and value both are confirmed
So B
SVP
SVP
User avatar
D
Joined: 26 Mar 2013
Posts: 2001
Reviews Badge CAT Tests
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 18 Feb 2016, 06:52
1
(1) |x|=2..........> X=2, X^3=8 or X=-2, X^3=-8 Ins

(2) 5x+6=16.....> X=2, X^3=8 Suf

Answer:B
Intern
Intern
User avatar
B
Joined: 30 Aug 2015
Posts: 31
Concentration: Marketing, Finance
WE: Brand Management (Manufacturing)
CAT Tests
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 18 Feb 2016, 15:48
2
(1) IXI=2
x=2,-2
so X^3=8,-8
not sufff..
(2) 5X+6=16

x=2
so X^3=8 suff.
Ans B . WE KNOW THAT MODS CAN BE POSITIVE OR NEGATIVE , SO WE CANT GET UNIQUE VALUES.
_________________

Please award kudos if you like my explanation.
Thanks :)

Director
Director
User avatar
G
Joined: 24 Nov 2015
Posts: 515
Location: United States (LA)
Reviews Badge
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 17 May 2016, 13:52
1
Statement 1 states |x|=2 which means that x can be either +2 or -2 so clearly insufficient as we would get 2 values of \(x^3\)
Statement 2 states 5x+6=16 which can simplified as 5x = 10 which gives x = 2 so we get a definite value of \(x^3\) which is \(2^3\) = \(8\)
so sufficient
correct answer - B
Senior Manager
Senior Manager
User avatar
Joined: 18 Jan 2010
Posts: 251
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 13 Jun 2016, 23:04
1
Bunuel wrote:
What is the value of x^3?

(1) |x|=2
(2) 5x+6=16

Kudos for correct solution.


Statement 1

x = 2 or x = -2. Value of \(x^3\) will be different in both cases. Not sufficient.

Statement 2

5x+6=16; 5x = 10; x = 2. We can get a unique value of \(x^3\) from this. Sufficient.

B is the answer.
Current Student
avatar
S
Joined: 26 Jun 2014
Posts: 78
Reviews Badge
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 11 Mar 2017, 18:50
MathRevolution wrote:
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

What is the value of x^3?

(1) |x|=2
(2) 5x+6=16


In the original condition, there is 1 variable(x), which should match with the number of equations. So you need 1 equation. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
For 1), x^3=-8,8 is derived from x=-2,2, which is not unique and not sufficient.
For 2), 5x=10, x=3, x^3=8 is derived, which is unique and sufficient.
Therefore, the answer is B.



 For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.


Thanks for sharing. But how is ti different from the conventional method?
Manager
Manager
avatar
B
Joined: 02 Jan 2017
Posts: 73
Location: Pakistan
Concentration: Finance, Technology
GMAT 1: 650 Q47 V34
GPA: 3.41
WE: Business Development (Accounting)
Reviews Badge
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 06 Dec 2017, 03:24
Bunuel wrote:
What is the value of x^3?

(1) |x|=2
(2) 5x+6=16

Kudos for correct solution.



Statement 1. |x|=2 , x can be either -2 or 2.
Therefore x^3 can have two values, 8 or -8.
Hence insufficient.

Statement 2.
Solving 5x +6 =16 will yield only one value of X
Therefore statement two is sufficient.

Answer is B
VP
VP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1364
Location: India
Concentration: International Business, Operations
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Premium Member Reviews Badge
Re: What is the value of x^3?  [#permalink]

Show Tags

New post 08 Mar 2018, 23:21
Bunuel wrote:
What is the value of x^3?

(1) |x|=2
(2) 5x+6=16

Kudos for correct solution.



Question: x^3 = ?

St 1: |x|=2

means x = 2 or -2, then x^3 will be 8 or -3. Insufficient

Even power always results in positive

Odd power holds the original sign of the variable.

St 2: 5x+6=16

x = 2

X^3 = 8

Sufficient

(B)
_________________

"Do not watch clock; Do what it does. KEEP GOING."

GMAT Club Bot
Re: What is the value of x^3? &nbs [#permalink] 08 Mar 2018, 23:21
Display posts from previous: Sort by

What is the value of x^3?

  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®.