|
Author |
Message |
|
TAGS:
|
|
|
Manager
Joined: 07 Oct 2005
Posts: 140
Location: Boston,MA
Followers: 1
Kudos [?]:
6
[0], given: 0
|
If n is an integer greater than 6, which of the following [#permalink]
 26 Nov 2007, 14:15
Question Stats:
69% (01:50) correct
30% (01:01) wrong based on 46 sessions
If n is an integer greater than 6, which of the following must be divisible by 3? A. n (n+1) (n-4) B. n (n+2) (n-1) C. n (n+3) (n-5) D. n (n+4) (n-2) E. n (n+5) (n-6)
_________________
--gregspirited
Last edited by Bunuel on 24 Mar 2012, 01:41, edited 1 time in total.
Added the OA
|
|
|
|
|
|
|
CEO
Joined: 17 Nov 2007
Posts: 3594
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 230
Kudos [?]:
1299
[0], given: 346
|
A.
All three numbers in product should have different reminders. Only A satisfies this requirement.
|
|
|
|
|
|
Manager
Joined: 29 Jul 2007
Posts: 184
Followers: 1
Kudos [?]:
9
[0], given: 0
|
question testing multiples of 3.
plug in 7 and 8 as test values.
A. n (n+1) (n-4) = 7*8*3 and if n = 8 --> 8*9*4
B. n (n+2) (n-1) = 7*9*6 and if n = 8 --> 8*10*7
C. n (n+3) (n-5) = 7*10*5; eliminate as there are no multiples of 3
D. n (n+4) (n-2) = 7*11*5; eliminate as there are no multiples of 3
E. n (n+5) (n-6) = 7*12*1 and and if n = 8 --> 8*13*2
only A works.
|
|
|
|
|
|
CEO
Joined: 29 Aug 2007
Posts: 2530
Followers: 41
Kudos [?]:
357
[0], given: 19
|
Re: PS - Integer N greater than 6 [#permalink]
26 Nov 2007, 15:29
gregspirited wrote: If n is an integer greater than 6, which of the following must be divisible by 3?
A. n (n+1) (n-4)
B. n (n+2) (n-1)
C. n (n+3) (n-5)
D. n (n+4) (n-2)
E. n (n+5) (n-6)
anything in the form of (n-1) (n) (n+1) is divvisible by 3. in other word, a product of any 3 consecutie intevers is divisible by 3.
A. n (n+1) (n-4) = n (n+1) ((n-1)-3) is equivalant to (n-1) (n) (n+1)
B. n (n+2) (n-1) is equivalant to (n+1) missing.
C. n (n+3) (n-5) is equivalant to (n-1) missing and n repeating.
D. n (n+4) (n-2) is equivalant to odd/even consqcutive integers
E. n (n+5) (n-6) is equivalant to (n+1) missing and n repeating.
So A is good.
|
|
|
|
|
|
Manager
Joined: 27 Oct 2011
Posts: 196
Location: United States
Concentration: Finance, Strategy
GMAT 1: Q V
GPA: 3.7
WE: Account Management (Consumer Products)
Followers: 1
Kudos [?]:
25
[0], given: 4
|
Re: If n is an integer greater than 6, which of the following [#permalink]
23 Mar 2012, 21:04
IMO A. I used an arbitrary number greater than 6 and then filled each equation out. if you happen to have chosen a number that makes more than 1 answer correct, choose a different number and check the ones that were previously correct.
_________________
DETERMINED TO BREAK 700!!!
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11526
Followers: 1795
Kudos [?]:
9551
[0], given: 826
|
Re: If n is an integer greater than 6, which of the following [#permalink]
24 Mar 2012, 01:40
gregspirited wrote: If n is an integer greater than 6, which of the following must be divisible by 3?
A. n (n+1) (n-4)
B. n (n+2) (n-1)
C. n (n+3) (n-5)
D. n (n+4) (n-2)
E. n (n+5) (n-6) Since 3 is a prime number then in order the product to be divisible by 3 either of the multiples must be divisible by 3. Now, to guarantee that at least one multiple is divisible by 3, these numbers must have different remainders upon division by 3, meaning that one of them should have the remainder of 1, another the reminder of 2 and the third one the remainder of 0, so be divisible by 3. For option A: n and n+1 have different remainder upon division by 3. As for n-4, it will have the same remainder as (n-4)+3=n-1, so also different than the remainders of the previous two numbers. Answer: A. Similar question to practice: if-x-is-an-integer-then-x-x-1-x-k-must-be-evenly-divisible-126853.htmlHope it helps.
_________________
PLEASE READ AND FOLLOW: 11 Rules for Posting!!!
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory
COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!!
DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!
What are GMAT Club Tests?
25 extra-hard Quant Tests
Find out what's new at GMAT Club - latest features and updates
|
|
|
|
|
|
Manager
Joined: 28 Jul 2011
Posts: 212
Followers: 0
Kudos [?]:
14
[0], given: 11
|
Re: If n is an integer greater than 6, which of the following [#permalink]
25 Mar 2012, 10:30
Bunuel wrote: gregspirited wrote: If n is an integer greater than 6, which of the following must be divisible by 3?
A. n (n+1) (n-4)
B. n (n+2) (n-1)
C. n (n+3) (n-5)
D. n (n+4) (n-2)
E. n (n+5) (n-6) Since 3 is a prime number then in order the product to be divisible by 3 either of the multiples must be divisible by 3. Now, to guarantee that at least one multiple is divisible by 3, these numbers must have different remainders upon division by 3, meaning that one of them should have the remainder of 1, another the reminder of 2 and the third one the remainder of 0, so be divisible by 3. For option A: n and n+1 have different remainder upon division by 3. As for n-4, it will have the same remainder as (n-4)+3=n-1, so also different than the remainders of the previous two numbers. Answer: A. Similar question to practice: if-x-is-an-integer-then-x-x-1-x-k-must-be-evenly-divisible-126853.htmlHope it helps. I liked the approach - Bookmaking it. Thank you Bunuel...
|
|
|
|
|
|
Manager
Joined: 30 May 2008
Posts: 72
Followers: 0
Kudos [?]:
0
[0], given: 16
|
Re: If n is an integer greater than 6, which of the following [#permalink]
15 Apr 2012, 17:12
Bunuel wrote: gregspirited wrote: If n is an integer greater than 6, which of the following must be divisible by 3?
A. n (n+1) (n-4)
B. n (n+2) (n-1)
C. n (n+3) (n-5)
D. n (n+4) (n-2)
E. n (n+5) (n-6) Since 3 is a prime number then in order the product to be divisible by 3 either of the multiples must be divisible by 3. Now, to guarantee that at least one multiple is divisible by 3, these numbers must have different remainders upon division by 3, meaning that one of them should have the remainder of 1, another the reminder of 2 and the third one the remainder of 0, so be divisible by 3. For option A: n and n+1 have different remainder upon division by 3. As for n-4, it will have the same remainder as (n-4)+3=n-1, so also different than the remainders of the previous two numbers. Answer: A. Similar question to practice: if-x-is-an-integer-then-x-x-1-x-k-must-be-evenly-divisible-126853.htmlHope it helps. Bunuel, could you please explain how you arrive at the conclusion that "As for n-4, it will have the same remainder as (n-4)+3=n-1"? Also, is it implied that n will have a remainder of either 0 or 1, n+1 will have either 1 or 2? Thanks!
|
|
|
|
|
|
Manager
Status: I will not stop until i realise my goal which is my dream too
Joined: 25 Feb 2010
Posts: 248
Followers: 2
Kudos [?]:
14
[0], given: 16
|
Re: If n is an integer greater than 6, which of the following [#permalink]
15 Apr 2012, 21:55
gregspirited wrote: If n is an integer greater than 6, which of the following must be divisible by 3?
A. n (n+1) (n-4)
B. n (n+2) (n-1)
C. n (n+3) (n-5)
D. n (n+4) (n-2)
E. n (n+5) (n-6) I went by the substitution method since n > 6 i took 7 and A,B and E were satisfied i took 8 and only A was satsified, hence the answer is A
_________________
Regards,
Harsha
Note: Give me kudos if my approach is right , else help me understand where i am missing.. I want to bell the GMAT Cat 
Satyameva Jayate - Truth alone triumphs
|
|
|
|
|
|
Director
Status: Gonna rock this time!!!
Joined: 22 Jul 2012
Posts: 551
Location: India
GMAT 1: 640 Q43 V34
GMAT 2: 630 Q47 V29
WE: Information Technology (Computer Software)
Followers: 1
Kudos [?]:
13
[0], given: 560
|
Re: PS - Integer N greater than 6 [#permalink]
24 Nov 2012, 21:56
GMAT TIGER wrote:
A. n (n+1) (n-4) = n (n+1) ((n-1)-3) is equivalant to (n-1) (n) (n+1)
So A is good.
Hi Bunuel, Why is n (n+1) (n-4) = n (n+1) ((n-1)-3) is equivalant to (n-1) (n) (n+1)? Also, you said.. Now, to guarantee that at least one multiple is divisible by 3, these numbers must have different remainders upon division by 3, meaning that one of them should have the remainder of 1, another the reminder of 2 and the third one the remainder of 0, so be divisible by 3.
For option A: n and n+1 have different remainder upon division by 3. As for n-4, it will have the same remainder as (n-4)+3=n-1Could you please elaborate the 2 statements above?
_________________
hope is a good thing, maybe the best of things. And no good thing ever dies.
Who says you need a 700 ?Check this out : http://gmatclub.com/forum/who-says-you-need-a-149706.html#p1201595
My GMAT Journey : end-of-my-gmat-journey-149328.html#p1198742
|
|
|
|
|
|
Manager
Joined: 29 Jul 2012
Posts: 188
GMAT Date: 11-18-2012
Followers: 0
Kudos [?]:
12
[0], given: 23
|
Re: If n is an integer greater than 6, which of the following [#permalink]
04 May 2013, 03:20
Hi Bunuel, Can you explain why the remainder should be different upon division by 3? I atill dint understood uproach Posted from my mobile device 
_________________
Thriving for CHANGE
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11526
Followers: 1795
Kudos [?]:
9551
[1] , given: 826
|
Re: If n is an integer greater than 6, which of the following [#permalink]
04 May 2013, 04:36
1
This post received
KUDOS
|
|
|
|
|
|
Intern
Joined: 05 Mar 2013
Posts: 6
Followers: 0
Kudos [?]:
2
[0], given: 4
|
Re: PS - Integer N greater than 6 [#permalink]
13 May 2013, 17:24
Sachin9 wrote: GMAT TIGER wrote:
A. n (n+1) (n-4) = n (n+1) ((n-1)-3) is equivalant to (n-1) (n) (n+1)
So A is good.
Hi Bunuel, Why is n (n+1) (n-4) = n (n+1) ((n-1)-3) is equivalant to (n-1) (n) (n+1)? For option A: n and n+1 have different remainder upon division by 3. As for n-4, it will have the same remainder as (n-4)+3=n-1[/i] i also dont understand this part, could you elaborate why ((n-1)-3) is equivalant to (n-1) (n) (n+1)? is it because the extra 3 remaining means it has zero remainder?
|
|
|
|
|
|
Intern
Joined: 24 Apr 2013
Posts: 37
Followers: 0
Kudos [?]:
0
[0], given: 49
|
Re: If n is an integer greater than 6, which of the following [#permalink]
14 May 2013, 13:27
I actually hit the answer by mistake before i got it. but i found this one easy
|
|
|
|
|
|
|
Re: If n is an integer greater than 6, which of the following
[#permalink]
14 May 2013, 13:27
|
|
|
|
|
|
|
|
|
Similar topics |
Author |
Replies |
Last post |
|
Similar
Topics:
|
 |
|
|
If n is an integer greater than 6, which of the following
|
ricokevin |
8 |
27 Mar 2007, 07:11 |
|
|
|
|
N is an integer greater than 6, which of the following must
|
Himalayan |
5 |
11 Jul 2007, 23:15 |
|
|
|
|
If n is an integer greater than 6, which of the following
|
marcodonzelli |
2 |
07 Jan 2008, 06:18 |
|
|
|
|
If n is an integer greater than 6, which of the following
|
marcodonzelli |
2 |
07 Mar 2008, 12:45 |
|
|
|
|
If n is an integer greater than 6, which of the following
|
tarek99 |
5 |
25 Jul 2008, 09:48 |
|
|
|
|
|
|
close
