If p and n are positive integers p >n , what is the : DS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 06:34

### 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 p and n are positive integers p >n , what is the

Author Message
VP
Joined: 30 Jun 2008
Posts: 1043
Followers: 14

Kudos [?]: 567 [0], given: 1

If p and n are positive integers p >n , what is the [#permalink]

### Show Tags

11 Oct 2008, 07:40
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 p and n are positive integers p >n , what is the remainder when p^2-n^2 is divided by 15

(1) The remainder when p+n is divided by 5 is 1
(2) The remainder when p-n is divided by 3 is 1
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Manager
Joined: 09 Oct 2008
Posts: 93
Followers: 1

Kudos [?]: 19 [0], given: 0

Re: DS : p and n are positive integers [#permalink]

### Show Tags

11 Oct 2008, 07:50
IMO C:

Please confirm ,i will give explanation after confirmation

(p-n)(p+n) is divisible by 15 ( 3 and 5 )or not..

A: it says remainder p+n is divided by 5 is 1.
7 + 4 =11 /5 ->reminder = 1 p-n= 3
8+4 = 11 /5-> reminder =1 p-n = 5

So A is not suff.

B:
remainder p-n is divided by 3 is 1
5 -4 = 1/3->reminder = 1 p+n = 9 divisible by 3
8-4 =1/3->reminder = 1 p+n=12 divisible by 3.
12-2=10/3->reminder=1 p+n= 14 not divisible by 3 or 5 but p-n is divisible by 5
So B is not suff.

A+ B
yes its suff. check it
Thanks
Intern
Joined: 14 Apr 2008
Posts: 41
Followers: 0

Kudos [?]: 3 [0], given: 0

Re: DS : p and n are positive integers [#permalink]

### Show Tags

11 Oct 2008, 09:37
IMO E.

Explanation below:

The questions ask for the remainder when (p^2-n^2) divided by 15 ~ (p-n)(p+n):15

(1): p+n=5i+1 -> not suf.

(2): p-n=3m+1 -> not suf.

(1) and (2) combined: (p-n)(p+n)=(5i+1)(3m+1)=15im+5i+3m+1 -> not suf. to determine the remainder 5i+3m+1

E it goes.
Manager
Joined: 10 Aug 2008
Posts: 76
Followers: 1

Kudos [?]: 13 [0], given: 0

Re: DS : p and n are positive integers [#permalink]

### Show Tags

11 Oct 2008, 09:49
I will go with madhusudan. For me ans is E)
Just take a exapmle

24/15 = 6x4/5x3 , when 6 divided by 5 than remainder is 1 & now when 4 divided by 3 again remainder is 1, But 24/15 has remainder 9
Current Student
Joined: 28 Dec 2004
Posts: 3384
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 15

Kudos [?]: 282 [0], given: 2

Re: DS : p and n are positive integers [#permalink]

### Show Tags

11 Oct 2008, 12:22
I get E as well..

(p+n)(p-n)=5K+r

P+N=5K+1

well p+n=6 then p-n=5-1=4...remainder would be 4..

p+n=16, then p-n=10-6=4 remainder would be 4..

if p+n=11, p-n=1 (i.e. 6-5) remainder would be 1..
Senior Manager
Joined: 21 Apr 2008
Posts: 269
Location: Motortown
Followers: 2

Kudos [?]: 143 [0], given: 0

Re: DS : p and n are positive integers [#permalink]

### Show Tags

11 Oct 2008, 13:30
E

Going with everybody's explanation:
Statement 1: Insufficient
Statement 2: Insufficient

Together :
If p+n = 6, you have to pick, p-n = 4 --> p=5, n=1
then,
R = 9

If p+n = 11, you have to pick p-n = 7 -->p=9, n= 2
then,
R = 2
Insufficient
Intern
Joined: 08 Oct 2008
Posts: 7
Followers: 0

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

Re: DS : p and n are positive integers [#permalink]

### Show Tags

12 Oct 2008, 22:20
I still dont understand, so the result is E or C
SVP
Joined: 17 Jun 2008
Posts: 1569
Followers: 11

Kudos [?]: 250 [0], given: 0

Re: DS : p and n are positive integers [#permalink]

### Show Tags

12 Oct 2008, 22:49
mimi28 wrote:
I still dont understand, so the result is E or C

Check the explanation from vishalgc.
Re: DS : p and n are positive integers   [#permalink] 12 Oct 2008, 22:49
Display posts from previous: Sort by