Welcome to the GRE Prep Club –the new and only GRE-focused community. Learn more about GRE Prep Club
close

It is currently 20 Jun 2018, 22:22
Search
Register
My Tests
New posts
Unanswered

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.

Go to My Workbook Learn more

0 < x < 1

  Question banks Downloads My Bookmarks Reviews Important topics  
 
Search for:
 
Print view
First unread post
Author Message
TAGS:
Moderator
Moderator
User avatar
Joined: 18 Apr 2015
Posts: 3715
Followers: 57

Kudos [?]: 620 [0], given: 3192

CAT Tests
0 < x < 1 [#permalink] New post 14 Oct 2017, 23:56
Expert's post
00:00

Question Stats:

45% (01:11) correct 54% (01:34) wrong based on 11 sessions


Quantity A
Quantity B
(x^3 - x)(4x + 3 )
(x^2 + 1)(4x^2 + 3x)


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
[Reveal] Spoiler: OA

_________________

Get the 2 FREE GREPrepclub Tests

1 KUDOS received
Director
Director
Joined: 03 Sep 2017
Posts: 521
Followers: 0

Kudos [?]: 292 [1] , given: 66

Re: 0 < x < 1 [#permalink] New post 16 Oct 2017, 02:01
1
This post received
KUDOS
Doing computations we get quantity A equal to 4x^4-4x^2+3x^3-3x and quantity B equal to 4x^4+4x^2+3x^3+3x. Now, simplifying we get A equal to -4x and B equal to 3. Then, whatever x between 0 and 1, B is greater!
1 KUDOS received
Intern
Intern
Joined: 23 Nov 2017
Posts: 44
Followers: 0

Kudos [?]: 42 [1] , given: 0

Re: 0 < x < 1 [#permalink] New post 15 Dec 2017, 04:14
1
This post received
KUDOS
IlCreatore wrote:
Doing computations we get quantity A equal to 4x^4-4x^2+3x^3-3x and quantity B equal to 4x^4+4x^2+3x^3+3x. Now, simplifying we get A equal to -4x and B equal to 3. Then, whatever x between 0 and 1, B is greater!


How did 4x^4+3x^3−4x^2+3x become 4x?
Moderator
Moderator
User avatar
Joined: 18 Apr 2015
Posts: 3715
Followers: 57

Kudos [?]: 620 [0], given: 3192

CAT Tests
Re: 0 < x < 1 [#permalink] New post 16 Dec 2017, 14:17
Expert's post
Here the best approach and that works really really fast is picking numbers.

For instance, you can choose an integer 1 or -1 or a fraction but the result will be the same.

Picking -1 the first quantity will be zero and the second will be 14. Same if you pick 1.and so on and so forth.

hope this helps.

Regards
_________________

Get the 2 FREE GREPrepclub Tests

1 KUDOS received
Intern
Intern
Joined: 17 Feb 2018
Posts: 31
Followers: 0

Kudos [?]: 23 [1] , given: 2

Re: 0 < x < 1 [#permalink] New post 23 Feb 2018, 19:58
1
This post received
KUDOS
a short cut:
extract one x from (x^3-x) we get x(x^2-1)(4x+3) on the left.
extract one x from (4x^2+3x) we get x(x^2+1)(4x+3) on the right.
x(4x+3) canceled out.
(x^2-1)<(x^2+1)
Intern
Intern
Joined: 24 Feb 2018
Posts: 15
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: 0 < x < 1 [#permalink] New post 24 Feb 2018, 17:09
B
1 KUDOS received
Manager
Manager
Joined: 22 Feb 2018
Posts: 84
Followers: 2

Kudos [?]: 57 [1] , given: 6

Re: 0 < x < 1 [#permalink] New post 12 Mar 2018, 16:49
1
This post received
KUDOS
correct: A (maybe includes miscalculatings!)
(x^3 - x)(4x + 3) = 4x^4 + 3x^3 - 4x^2 -3x

(x^2 + 1)(4x^2 + 3x) = 4x^4 + 3x^3 + 4x^2 + 3x

We compare these two and simplify as much as possible.
4x^4 + 3x^3 - 4x^2 -3x vs 4x^4 + 3x^3 + 4x^2 + 3x
Omitting 4x^4 + 3x^3:
- 4x^2 -3x vs 4x^2 + 3x
-(4x^2 + 3x) vs (4x^2 + 3x)
a) When 4x^2 + 3x is negative then the value in the left will be positive when multiplied by it’s negative sign. And the right value will be negative and thus less.
4x^2 + 3x < 0 —> 4x^2 < -3x —> x < -3/4
b) When 4x^2 + 3x is positive the value in the right will be bigger.
4x^2 + 3x > 0 —> 4x^2 > -3x —> x > -3/4

BUT
it's mentioned that x is between 0 and 1 and it will be case b. so A is bigger than B
Re: 0 < x < 1   [#permalink] 12 Mar 2018, 16:49
Display posts from previous: Sort by

0 < x < 1

  Question banks Downloads My Bookmarks Reviews Important topics  
Print view
First unread post

Moderators: GreenlightTestPrep, IlCreatore, pranab01, Moderators

Search for:


cron

GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.

Main navigation

Partners

GRE Resources

www.ets.org/gre