Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 24 May 2013, 12:38
Customize  |  Hide

Search
Register
New posts
Unanswered

If n is an integer greater than 6, which of the following

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
SVP
SVP
Joined: 21 Jul 2006
Posts: 1553
Followers: 6

Kudos [?]: 104 [0], given: 1

GMAT Tests User
If n is an integer greater than 6, which of the following [#permalink] New post 25 Jul 2008, 09:48
00:00

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If n is an integer greater than 6, which of the following must be divisible by 3?

a) n(n+2)(n+3)

b) n(n+5)(n-3)

c) n(n+2)(n+5)

d) n(n+1)(n-4)

e) n(n+1)(n-2)




I chose A as my answer, but it's wrong. How come??? whenever we have 3 consecutive numbers, obviously one of them will always be a multiple of 3. I really don't understand why it is wrong this time! :?
Current Student
Joined: 28 Dec 2004
Posts: 3439
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11

Kudos [?]: 134 [0], given: 2

GMAT Tests User
Re: PS: In [#permalink] New post 25 Jul 2008, 09:56
tarek99 wrote:
If n is an integer greater than 6, which of the following must be divisible by 3?

a) n(n+2)(n+3)

b) n(n+5)(n-3)

c) n(n+2)(n+5)

d) n(n+1)(n-4)

e) n(n+1)(n-2)


you want to ensure that the ans choice contains at least a 3 and an even number

if n>6, then look at 7-4=3, 8-4=4 but 8+1=9.. 11-4=7 but 11+1=12 which is a multiple of 3..

so based on this D is the only choice that will always ensure that there is a 3 and an even number..
Director
Director
Joined: 23 Sep 2007
Posts: 806
Followers: 4

Kudos [?]: 66 [0], given: 0

GMAT Tests User
Re: PS: In [#permalink] New post 25 Jul 2008, 09:57
choice A is NOT 3 consec integers

tarek99 wrote:
If n is an integer greater than 6, which of the following must be divisible by 3?

a) n(n+2)(n+3)

b) n(n+5)(n-3)

c) n(n+2)(n+5)

d) n(n+1)(n-4)

e) n(n+1)(n-2)




I chose A as my answer, but it's wrong. How come??? whenever we have 3 consecutive numbers, obviously one of them will always be a multiple of 3. I really don't understand why it is wrong this time! :?
Senior Manager
Senior Manager
User avatar
Joined: 07 Jan 2008
Posts: 418
Followers: 2

Kudos [?]: 46 [0], given: 0

GMAT Tests User
Re: PS: In [#permalink] New post 25 Jul 2008, 10:06
D: n(n+1)(n-4) Image(n-1)(n)(n+1) (mod 3)
Current Student
User avatar
Joined: 31 Aug 2007
Posts: 374
Followers: 1

Kudos [?]: 36 [0], given: 1

GMAT Tests User
Re: PS: In [#permalink] New post 25 Jul 2008, 10:20
I say D...I don't even see why we would need the info that n>6 to answer this question....
do we?
SVP
SVP
User avatar
Joined: 07 Nov 2007
Posts: 1842
Location: New York
Followers: 20

Kudos [?]: 291 [0], given: 5

GMAT Tests User
Re: PS: In [#permalink] New post 25 Jul 2008, 10:23
tarek99 wrote:
If n is an integer greater than 6, which of the following must be divisible by 3?

a) n(n+2)(n+3)

b) n(n+5)(n-3)

c) n(n+2)(n+5)

d) n(n+1)(n-4)

e) n(n+1)(n-2)




I chose A as my answer, but it's wrong. How come??? whenever we have 3 consecutive numbers, obviously one of them will always be a multiple of 3. I really don't understand why it is wrong this time! :?


I chose D too..
here is the strategy


...(n-3)(n-2) (n-1) ..... n (n+1) (n+2) .... (n+3)(n+4)(n+5)..
--> multiple of any three consecutive positive numbers defnitiely divsiable by 3.

n (n+1) (n+2) --- > must divisible by 3
(n-6)(n-5)(n-4)...(n-3)(n-2) (n-1) ..... n (n+1) (n+2) .... (n+3)(n+4)(n+5)..

for any one number if substract or add 3(or multiples of 3) ..then it must divisible by 3.
n (n+1) (n+2 -3)= n (n+1) (n-1)
n (n+1) (n+2 -3*2)= n (n+1) (n-4)
n (n+1) (n+2 +3)= n (n+1) (n+5)
n (n+1) (n+2 +3*2)= n (n+1) (n+8)

---------
By above strategy (substraction or addition .. to any numbers) I try to see if any answer choice will lead to three consecutive numbers..

a) n(n+2)(n+3) -- out not consecutive numbers...
b) n(n+5)(n-3) --> n (n+2) n --out not consecutive numbers...
subtract 3 from (n+5) add 3 to (n-3)
c) n(n+2)(n+5) -->n(n+2)(n+2) --out not consecutive numbers
subtract 3 from (n+5)
d) n(n+1)(n-4) -->n(n+1)(n-1) -- consecutive numbers
add 3 to (n-4)
e) n(n+1)(n-2) --> n(n+1)(n+1) out not consecutive numbers
_________________

Your attitude determines your altitude
Smiling wins more friends than frowning

Re: PS: In   [#permalink] 25 Jul 2008, 10:23
    Similar topics Author Replies Last post
Similar
Topics:
 New posts If n is an integer greater than 6, which of the following ricokevin 8 27 Mar 2007, 07:11
New posts N is an integer greater than 6, which of the following must Himalayan 5 11 Jul 2007, 23:15
Popular new posts 1 EXPERTS_POSTS_IN_THIS_TOPIC If n is an integer greater than 6, which of the following gregspirited 13 26 Nov 2007, 14:15
New posts If n is an integer greater than 6, which of the following marcodonzelli 2 07 Jan 2008, 06:18
New posts If n is an integer greater than 6, which of the following marcodonzelli 2 07 Mar 2008, 12:45
Display posts from previous: Sort by

If n is an integer greater than 6, which of the following

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma, IanStewart

Search for:


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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com