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when n is devided by 4, the remiander is 3. the remainder [#permalink]
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05 Oct 2007, 15:07
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This topic is locked. If you want to discuss this question please repost it in the respective forum. when n is devided by 4, the remiander is 3. the remainder when 2n is devided by 4 is
a] 1
b] 2
c] 3
d] 6
e] 4
I am sort of on the right track here, but cant quite understand the last step. Ill post the OA in a bit. Oh, post your explanations as well



VP
Joined: 08 Jun 2005
Posts: 1145

n/4 = y & remiander(3)
This can be expressed as:
4*y+3 = n
and
2*n = 2*(4*y+3) = 8*y+6
Easy to test > assume y=2
See bluebird's post
Last edited by KillerSquirrel on 05 Oct 2007, 15:54, edited 1 time in total.



Manager
Joined: 18 Apr 2007
Posts: 120

I'm getting B....
n/4 = Q+3
Therefore, n=7,11,15,19,etc.
Using these values, 2n = 14,22,30,38,etc.
each of these values divided by 4 leaves a remainder of 2
Answer: B



Director
Joined: 22 Aug 2007
Posts: 566

Re: PS: Remainder question [#permalink]
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05 Oct 2007, 15:43
pmenon wrote: when n is devided by 4, the remiander is 3. the remainder when 2n is devided by 4 is a] 1 b] 2 c] 3 d] 6 e] 4 I am sort of on the right track here, but cant quite understand the last step. Ill post the OA in a bit. Oh, post your explanations as well
B,
remainder is also multiplied by 2, so 6/4=1 plus remainder 2/4.
EDITTED*
Last edited by IrinaOK on 05 Oct 2007, 17:10, edited 1 time in total.



VP
Joined: 08 Jun 2005
Posts: 1145

Bluebird wrote: I'm getting B....
n/4 = Q+3 Therefore, n=7,11,15,19,etc.
Using these values, 2n = 14,22,30,38,etc. each of these values divided by 4 leaves a remainder of 2
Answer: B
Yes you are correct !
the answer is (B)



VP
Joined: 09 Jul 2007
Posts: 1100
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Re: PS: Remainder question [#permalink]
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05 Oct 2007, 16:02
pmenon wrote: when n is devided by 4, the remiander is 3. the remainder when 2n is devided by 4 is a] 1 b] 2 c] 3 d] 6 e] 4 I am sort of on the right track here, but cant quite understand the last step. Ill post the OA in a bit. Oh, post your explanations as well
the best strategy to apply is picking numbers to save time;
7 fine remainder 3, > 14 remainder is 2
15 fine remainder 3, > 30 remainder is 2
19 fine remainder 3, > 38 remainder is 2
so B



SVP
Joined: 28 Dec 2005
Posts: 1558

OA is B
I was approaching the question using formulas, but got stuck at this point:
n=4q+3
2n=8q+6
from here, without picking numbers, how do you figure out that the remainder is 2 ?



VP
Joined: 09 Jul 2007
Posts: 1100
Location: London

pmenon wrote: OA is B I was approaching the question using formulas, but got stuck at this point: n=4q+3 2n=8q+6 from here, without picking numbers, how do you figure out that the remainder is 2 ?
i would not even attempt it with formulaes. now try to divide the final equation by four. u will not have chance to determine it then.
better use picking numbers as u save time for other questions










