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

It is currently 17 Nov 2018, 17:45

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
  • FREE Quant Workshop by e-GMAT!

     November 18, 2018

     November 18, 2018

     07:00 AM PST

     09:00 AM PST

    Get personalized insights on how to achieve your Target Quant Score. November 18th, 7 AM PST
  • 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.

4(xy)^3 + (x^3 − y^3)^2 =

  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: 50623
4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 01 Jun 2017, 11:00
1
3
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

84% (01:28) correct 16% (02:02) wrong based on 131 sessions

HideShow timer Statistics

Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 2104
Premium Member CAT Tests
4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 01 Jun 2017, 11:52
Bunuel wrote:
\(4(xy)^3 + (x^3 − y^3)^2 =\)


(A) \(x^3 − y^3\)

(B) \((x^2 + y^2)^3\)

(C) \((x^3 + y^3)^3\)

(D) \((x^3 − y^3)^2\)

(E) \((x^3 + y^3)^2\)


\(4(xy)^3 + (x^3 − y^3)^2 =\) - expand the Square of a Difference:

\(4(xy)^3\) + \(x^6 - (2)(xy)^3 + y^6\) =

\(x^6 + (2)(xy)^3 + y^6\) = the expanded version of Square of a Sum ==>

\((x^3 + y^3)^2\)

Answer
Manager
Manager
avatar
G
Joined: 04 Jan 2016
Posts: 166
Location: United States (NY)
GMAT 1: 620 Q44 V32
GMAT 2: 600 Q48 V25
GMAT 3: 660 Q42 V39
GPA: 3.48
GMAT ToolKit User Premium Member
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 04 Jun 2017, 11:44
1
We have

\(4(xy)^3 + (x^3 - y^3)^2 = > 4(xy)^3 + x^6 - 2(xy)^3 + y^6 = x^6 + 2(xy)^3 + y^6 = (x^3+y^3)^2\)

Therefore, the answer is option E

Hit the K
DS Forum Moderator
avatar
P
Joined: 21 Aug 2013
Posts: 1365
Location: India
Premium Member
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 04 Jun 2017, 23:42
This can also be solved by plugging in values. Lets assume x = y = 1.
So 4(xy)^3 + (x^3 − y^3)^2 = 4 *(1*1)^2 + (1-1)^2 = 4.

Thus we have to look for an option where when we put x=1 and y=1, we should get our answer as '4'.

Check A) 1-1 = 0
B) (1+1)^3 = 8
C) (1+1)^3 = 8
D) (1-1)^2 = 0
E) (1+1)^2 = 4

Only E satisfies. Thus E answer
Intern
Intern
avatar
Joined: 23 May 2017
Posts: 5
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 05 Jun 2017, 02:18
amanvermagmat wrote:
This can also be solved by plugging in values. Lets assume x = y = 1.
So 4(xy)^3 + (x^3 − y^3)^2 = 4 *(1*1)^2 + (1-1)^2 = 4.

Thus we have to look for an option where when we put x=1 and y=1, we should get our answer as '4'.

Check A) 1-1 = 0
B) (1+1)^3 = 8
C) (1+1)^3 = 8
D) (1-1)^2 = 0
E) (1+1)^2 = 4

Only E satisfies. Thus E answer


4x^3*y^3 + x^6 - 2(x^3- y^3) + y^6. On opening up the brackets we get, 4x^3*y^3 + x^6 - 2x^3y^3 + y^6. Cancel out 4x^3y^3 and 2x^3y^3. Finally we get, x^6 + 2x^3y^3 +y^6. Therefore, the answer is E.
Manager
Manager
User avatar
S
Joined: 09 Dec 2015
Posts: 114
Location: India
Concentration: General Management, Operations
Schools: IIMC (A)
GMAT 1: 700 Q49 V36
GPA: 3.5
WE: Engineering (Consumer Products)
Reviews Badge
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 07 Jun 2017, 03:40
4(xy)^3 + (x^3-y^3)^2
= 4(xy)^3 + x^6 + y^6 -2(xy)^3
= x^6 + y^6 +2(xy)^3
= (x^3 + y^3)^2.

Option E is should be the correct answer, waiting for OA :)
Intern
Intern
avatar
S
Joined: 18 Jun 2015
Posts: 49
GMAT 1: 760 Q49 V44
Premium Member Reviews Badge
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 07 Jun 2017, 04:21
=4(xy)^3 + (x^6 - 2(xy)^3 + y^6)
=2(xy)^3 +x^6 +y^6
=(x^3 + y^3)^2

Hence, the answer should be E.

I would appreciate a kudos if you liked my solution!
Senior PS Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 3307
Location: India
GPA: 3.12
Premium Member CAT Tests
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 07 Jun 2017, 04:27
Let x=y=1

The expression \(4(xy)^3 + (x^3 − y^3)^2\) gives us a value of 4

Evaluating the answer choices, Only \((x^3+y^3)^2\)(Option E) gives us the same value
_________________

You've got what it takes, but it will take everything you've got

Manager
Manager
User avatar
B
Joined: 19 Jul 2017
Posts: 85
Location: India
Concentration: General Management, Strategy
GPA: 3.5
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 27 Aug 2017, 23:21
4(xy)^3+x^6-2x^3y^3+y^3
=x^6+y^6+2x^3y^3
=(x^3+y^3)^2

Hence Option E
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 31 Aug 2017, 09:21
Bunuel wrote:
\(4(xy)^3 + (x^3 − y^3)^2 =\)


(A) \(x^3 − y^3\)

(B) \((x^2 + y^2)^3\)

(C) \((x^3 + y^3)^3\)

(D) \((x^3 − y^3)^2\)

(E) \((x^3 + y^3)^2\)


4(xy)^3 + (x^3 - y^3)^2

4x^3y^3 + x^6 - 2x^3y^3 + y^6

x^6 + 2x^3y^3 + y^6

(x^3 + y^3)^2

Answer: E
_________________

Jeffery Miller
Head of GMAT Instruction

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8801
Premium Member
Re: 4(xy)^3 + (x^3 − y^3)^2 =  [#permalink]

Show Tags

New post 21 Sep 2018, 11:54
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: 4(xy)^3 + (x^3 − y^3)^2 = &nbs [#permalink] 21 Sep 2018, 11:54
Display posts from previous: Sort by

4(xy)^3 + (x^3 − y^3)^2 =

  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®.