Find all School-related info fast with the new School-Specific MBA Forum

It is currently 09 Jul 2014, 22:18

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If n is odd, then n(n*n - 1) is divisible by: 1. 9 2. 10 3.

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 28 Jun 2004
Posts: 90
Followers: 1

Kudos [?]: 2 [0], given: 0

If n is odd, then n(n*n - 1) is divisible by: 1. 9 2. 10 3. [#permalink] New post 22 Aug 2004, 08:16
If n is odd, then n(n*n - 1) is divisible by:

1. 9
2. 10
3. 7
4. 24
Senior Manager
Senior Manager
avatar
Joined: 19 May 2004
Posts: 291
Followers: 1

Kudos [?]: 4 [0], given: 0

GMAT Tests User
 [#permalink] New post 22 Aug 2004, 11:38
I pick D. 24.

n(n*n - 1) = n(n^2 - 1) = n(n-1)(n+1)
Since this is a product of 3 consecutive integers, the number is divisible by 3.

Moreover, An odd number can be expressed mathematically as 2k+1.

Here (2k+1)(2k)(2k+2) = 4*k*(k+1)*(2k+1) which means that the number is also divisible by 8. (k*(k+1) would be even)

3*8=24.
Manager
Manager
avatar
Joined: 28 Jun 2004
Posts: 90
Followers: 1

Kudos [?]: 2 [0], given: 0

 [#permalink] New post 22 Aug 2004, 11:50
The way I figured it is, 9 and 7 are automatically out as the number is atleast divisible by 3 and 2. That leaves 10 and 24. 10 is also out. Thus 24 has to be the answer.
Joined: 31 Dec 1969
Location: United States
Concentration: Marketing, Other
GMAT 1: 710 Q49 V38
GMAT 2: 660 Q V
GPA: 3.64
WE: Accounting (Accounting)
Followers: 0

Kudos [?]: 49 [0], given: 74536

 [#permalink] New post 22 Aug 2004, 14:07
smcgrath12 wrote:
The way I figured it is, 9 and 7 are automatically out as the number is atleast divisible by 3 and 2. That leaves 10 and 24. 10 is also out. Thus 24 has to be the answer.


how did you eliminated 10?
Manager
Manager
avatar
Joined: 28 Jun 2004
Posts: 90
Followers: 1

Kudos [?]: 2 [0], given: 0

 [#permalink] New post 22 Aug 2004, 16:03
Anonymous wrote:

how did you eliminated 10?


The way I thought is, if 3 is a divisor, than 10 cannot be. Also if 10 is the divisor, than 5 has to be, and there is nothing to suggest 5 is.
  [#permalink] 22 Aug 2004, 16:03
    Similar topics Author Replies Last post
Similar
Topics:
Is the integer n odd? (1) n is divisible by 3 (2) 2n is Achilless 4 20 Aug 2006, 20:16
Is the integer n odd? (1) n is divisible by 3. (2) 2n is dinesh8 3 03 Jun 2006, 22:24
Is the integer n odd? (1) n is divisible by 3 (2) 2 n is TeHCM 3 26 Dec 2005, 17:18
Is the integer n odd? (1) n is divisible by 3 (2) 2n is chunjuwu 2 25 Jan 2005, 04:55
Is the integer N odd? (1) N is divisible by 3 (2)2N is saurya_s 7 03 Oct 2004, 11:51
Display posts from previous: Sort by

If n is odd, then n(n*n - 1) is divisible by: 1. 9 2. 10 3.

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.