It is currently 18 Mar 2018, 23:40

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If n is a positive integer and r is the remainder, when

Author Message
Manager
Joined: 14 Jun 2008
Posts: 162
If n is a positive integer and r is the remainder, when [#permalink]

### Show Tags

25 Aug 2008, 02:24
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

Last edited by sset009 on 25 Aug 2008, 13:57, edited 1 time in total.
Senior Manager
Joined: 16 Jul 2008
Posts: 285

### Show Tags

25 Aug 2008, 05:45
If this is a DS question, please post the two statements. If not, I cannot solve this.
_________________

http://applicant.wordpress.com/

Manager
Joined: 14 Jun 2008
Posts: 162

### Show Tags

25 Aug 2008, 13:58
oops
corrected
Senior Manager
Joined: 16 Jul 2008
Posts: 285

### Show Tags

26 Aug 2008, 00:11
I think C. With number picking the remainder is always 0. What is the OA?
_________________

http://applicant.wordpress.com/

Senior Manager
Joined: 06 Apr 2008
Posts: 401

### Show Tags

26 Aug 2008, 00:57
sset009 wrote:
If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

IMO C)

Pick 1 and all prime numbers other than 2,3 the remainder is always 0
Manager
Joined: 20 May 2008
Posts: 55

### Show Tags

26 Aug 2008, 05:10
IMO C.

1 is insuff.
if n=5,7,9 do not have 2 as a factor but when (n-1)(n+1) is divided by 24, we get remainders 0,0,8 respectively.

2. is insuff.
if n = 5,7,10 do not have 3 as a factor and when (n-1)(n+1) is divided by 24, we get remainders 0,0,3 respectively.

1 and 2 taken together give n=5,7,11,13 etc and all have a remainder 0 when (n-1)(n+1) is divided by 24.
Director
Joined: 12 Jul 2008
Posts: 513
Schools: Wharton

### Show Tags

26 Aug 2008, 05:24
sset009 wrote:
If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

(1) Insufficient

Implies n is an odd number.

If n = 3, (n-1)(n+1) = 8
If n = 5, (n-1)(n+1) = 24

(2) Insufficient

n can be any even number or any odd number that is not a multiple of 3

If n = 2, (n-1)(n+1) = 3
If n = 5, (n-1)(n+1) = 24

(1) & (2) Sufficient

n is any odd number that is not a multiple of 3

For all of these n, (n-1)(n+1) is divisible by 24. Pick a few random numbers to be sure.

If n = 13, (n-1)(n+1) = 12*14 = 24*7
If n = 35, (n-1)(n+1) = 34*36 = 2*17*3*12 =24*17*3
SVP
Joined: 07 Nov 2007
Posts: 1765
Location: New York

### Show Tags

26 Aug 2008, 08:08
sset009 wrote:
If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

I will go for E.

n=5 (n-1)(n+1) =4*6=24 remainder 0
n=7 (n-1)(n+1) = 8*10 =80 remainder 8
_________________

Smiling wins more friends than frowning

Senior Manager
Joined: 16 Jul 2008
Posts: 285

### Show Tags

26 Aug 2008, 08:55
x2suresh wrote:
sset009 wrote:
If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

I will go for E.

n=5 (n-1)(n+1) =4*6=24 remainder 0
n=7 (n-1)(n+1) = 8*10 =80 remainder 8

n=7 (n-1)(n+1) = 6*8 = 48 remainder 0
_________________

http://applicant.wordpress.com/

SVP
Joined: 07 Nov 2007
Posts: 1765
Location: New York

### Show Tags

26 Aug 2008, 10:54
Nerdboy wrote:
x2suresh wrote:
sset009 wrote:
If n is a positive integer and r is the remainder, when (n-1)(n+1) is divided by 24, what is teh value of R

1) 2 is not a factor of n
2) 3 is not a factor of n

I will go for E.

n=5 (n-1)(n+1) =4*6=24 remainder 0
n=7 (n-1)(n+1) = 8*10 =80 remainder 8

n=7 (n-1)(n+1) = 6*8 = 48 remainder 0

you are right!!!!
_________________

Smiling wins more friends than frowning

Re: Remaind DS   [#permalink] 26 Aug 2008, 10:54
Display posts from previous: Sort by