It is currently Mon Mar 15, 2010 12:27 am
Image
GMAT ToolKit becomes an open platform for test takers and Prep companies!

Additional 236 questions from our partner Manhattan Review are already available. Update your application for free.

Manhattan Review Discount: Save 10% and free GMAT Club Tests




Post new topic Reply to topic  [ 6 posts ]  Bookmark and Share
Author Message
TAGS:
 Post subject: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 3:38 am 
Offline
Manager
Manager

Joined: Mon Nov 19, 2007
Posts: 236

Kudos (?): 27 (0), given: 1

For how many values of k is 12^12 the least common multiple of the positive integers 6^6, 8^8 and k?

A. 23
B. 24
C. 25
D. 26
E. 27


Top
 Profile  
 
 Post subject: Re: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 4:12 am 
Offline
Manager
Manager
User avatar

Joined: Thu Oct 29, 2009
Posts: 217

Kudos (?): 96 (0), given: 18

jade3 wrote:
For how many values of k is 12^12 the least common multiple of the positive integers 6^6, 8^8 and k?

A. 23
B. 24
C. 25
D. 26
E. 27



6^6 = (2^6)*(3^6)

8^8 = 2^{24}

Now we know that the least common multiple of the above two numbers and k is:

12^{12} = (2*2*3)^{12} = (2^{24})*(3^{12})

Thus, k will also be in the form of : (2^a)*(3^b)

Now, b has to be equal to 12 since in order for (2^{24})*(3^{12}) to be a common multiple, at least one of the numbers must have the terms 2^{24} and 3^{12} as its factors. (not necessarily the same number).

We can see that 8^8 already takes care of the 2^{24} part.
Thus, k has to take care of the 3^{12} part of the LCM.

This means that the value k is (2^a)*(3^{12}) where a can be any value from 0 to 24 (both inclusive) without changing the value of the LCM.

Thus K can have 25 values. Choice (c).

Cheers.

_________________
Click below to check out some great tips and tricks to help you deal with problems on Remainders!
compilation-of-tips-and-tricks-to-deal-with-remainders-86714.html#p651942

Word Problems Made Easy!
1) Translating the English to Math : word-problems-made-easy-87346.html
2) 'Work' Problems Made Easy : work-word-problems-made-easy-87357.html
3) 'Distance/Speed/Time' Word Problems Made Easy : distance-speed-time-word-problems-made-easy-87481.html


Top
 Profile  
 
 Post subject: Re: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 4:15 am 
Offline
Manager
Manager
User avatar

Joined: Thu Oct 29, 2009
Posts: 217

Kudos (?): 96 (0), given: 18

Quote:
8^8 = 2^24


8^8 = 2^(24)

Similarly for the other numbers.

Sorry for that confusion. Wasn't able to get a 2 digit power using the math function. If any one knows how to do it please do let me know.
Cheers.

_________________
Click below to check out some great tips and tricks to help you deal with problems on Remainders!
compilation-of-tips-and-tricks-to-deal-with-remainders-86714.html#p651942

Word Problems Made Easy!
1) Translating the English to Math : word-problems-made-easy-87346.html
2) 'Work' Problems Made Easy : work-word-problems-made-easy-87357.html
3) 'Distance/Speed/Time' Word Problems Made Easy : distance-speed-time-word-problems-made-easy-87481.html


Top
 Profile  
 
 Post subject: Re: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 4:42 am 
Offline
GMAT Quant Forum Moderator
User avatar

Joined: Wed Sep 02, 2009
Posts: 1215

Kudos (?): 521 (0), given: 58

sriharimurthy wrote:
Quote:
8^8 = 2^24


8^8 = 2^(24)

Similarly for the other numbers.

Sorry for that confusion. Wasn't able to get a 2 digit power using the math function. If any one knows how to do it please do let me know.
Cheers.


Edited your post. Please check if I didn't mess it up accidentally. To get two digit power just put the power in {}, eg. 2^{24} and mark with [m] button.

_________________
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation
DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities


Top
 Profile  
 
 Post subject: Re: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 4:53 am 
Offline
Manager
Manager
User avatar

Joined: Thu Oct 29, 2009
Posts: 217

Kudos (?): 96 (0), given: 18

Bunuel wrote:
Edited your post. Please check if I didn't mess it up accidentally. To get two digit power just put the power in {}, eg. 2^{24} and mark with m button.



Nope, you didn't mess it up.. Only made it better! Thanks Brunel!
Infact thanks^{10} !! :wink:

_________________
Click below to check out some great tips and tricks to help you deal with problems on Remainders!
compilation-of-tips-and-tricks-to-deal-with-remainders-86714.html#p651942

Word Problems Made Easy!
1) Translating the English to Math : word-problems-made-easy-87346.html
2) 'Work' Problems Made Easy : work-word-problems-made-easy-87357.html
3) 'Distance/Speed/Time' Word Problems Made Easy : distance-speed-time-word-problems-made-easy-87481.html


Top
 Profile  
 
 Post subject: Re: least common multiple -12^12 [#permalink]
PostPosted: Thu Nov 12, 2009 8:43 am 
Offline
Manager
Manager

Joined: Mon Nov 19, 2007
Posts: 236

Kudos (?): 27 (0), given: 1

sriharimurthy wrote:

6^6 = (2^6)*(3^6)

8^8 = 2^{24}

Now we know that the least common multiple of the above two numbers and k is:

12^{12} = (2*2*3)^{12} = (2^{24})*(3^{12})

Thus, k will also be in the form of : (2^a)*(3^b)

Now, b has to be equal to 12 since in order for (2^{24})*(3^{12}) to be a common multiple, at least one of the numbers must have the terms 2^{24} and 3^{12} as its factors. (not necessarily the same number).

We can see that 8^8 already takes care of the 2^{24} part.
Thus, k has to take care of the 3^{12} part of the LCM.

This means that the value k is (2^a)*(3^{12}) where a can be any value from 0 to 24 (both inclusive) without changing the value of the LCM.

Thus K can have 25 values. Choice (c).

Cheers.


You are spot on
The answer is indeed C


Top
 Profile  
 
Online
gmatclubot
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

Related Discussions

Forum

DS - greatest common factor and least common multiple GMAT Math Questions and Intellectual Discussions
common multiple GMAT Problem Solving (PS)
least common multiple GMAT Problem Solving (PS)
If the least common multiple of a positive integer GMAT Math Questions and Intellectual Discussions
Is it common to jump from job to job for WE? The B-School Application


Who is online

Users browsing this forum: No registered users and 0 guests


Search for:
Jump to:




GMAT Club MBA Forum Home | Sitemap | About | Privacy Policy | Terms and Conditions | GMAT Club Rules | Contact
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Kindly note that GMAT (C) is a registered trademark of the Graduate Management Admission Council, and this site has neither been reviewed nor endorsed by GMAC.