It is currently 11 Dec 2018, 18:56
My Tests

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.

x > 0 and x^4 = 625

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Moderator
Moderator
User avatar
Joined: 18 Apr 2015
Posts: 5149
Followers: 77

Kudos [?]: 1030 [1] , given: 4638

CAT Tests
x > 0 and x^4 = 625 [#permalink] New post 05 Mar 2017, 08:41
1
This post received
KUDOS
Expert's post
00:00

Question Stats:

80% (00:31) correct 19% (00:46) wrong based on 46 sessions


\(x > 0\) and \(x^4 = 625\)

Quantity A
Quantity B
The greatest prime factor of 36x
x




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

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4749
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1654 [0], given: 396

CAT Tests
Re: x > 0 and x^4 = 625 [#permalink] New post 11 Mar 2017, 06:57
Expert's post
Explanation

First, find x:
\(x^4 = 625\) or \(x = 5\) or \(-5\)

However, the question states that x > 0, so x = 5

Now find 36x:

\(36x\) or \((36)(5)\) or \(180\).

Now prime factors of 180 are 2, 3, and 5.

Prime factors of 5 is 5.

Greatest prime factor of both the quantities is 5. Hence C is correct.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

1 KUDOS received
Manager
Manager
Joined: 22 Feb 2018
Posts: 120
Followers: 2

Kudos [?]: 71 [1] , given: 14

CAT Tests
Re: x > 0 and x^4 = 625 [#permalink] New post 16 Mar 2018, 16:26
1
This post received
KUDOS
correct: C
x^4 = 625
x = 5 (x > 0 so x can't be -5)
36x = 36 * 5 or 36 * -5
36 * 5 = 2 * 2 * 3 * 3 * 5 = 2^2 * 3^2 * 5 The prime factors are 2, 3 and 5. So the biggest prime factor of 36*x is 5

_________________

Follow your heart

1 KUDOS received
Manager
Manager
User avatar
Joined: 15 Jan 2018
Posts: 147
GMAT 1: Q V
Followers: 3

Kudos [?]: 174 [1] , given: 0

Re: x > 0 and x^4 = 625 [#permalink] New post 17 Mar 2018, 08:44
1
This post received
KUDOS
625 is a fairly common number on the GRE along with other powers of 5. Whenever I have a variable on a QC I like to ask myself can the number be Pos/neg, integer/non-int, or 0. Because \(x^4\) is an integer, I know that X is also an integer, and that it must be positive (therefore not 0) as well.

Therefore, I know X is positive 5. For the greatest prime factor, I don't ever need to multiply 36 and 5 together. I can just do the prime factorization of 36 (2-2-3-3) and I have 5 so the greatest prime factor is 5 and both quantities are equal.

Remember if you can get away with not doing math on the quant section that's the way to go! :twisted:
_________________

-
-
-
-
-

Need help with GRE math? Check out our ground-breaking books and app.

Re: x > 0 and x^4 = 625   [#permalink] 17 Mar 2018, 08:44
Display posts from previous: Sort by

x > 0 and x^4 = 625

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.