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Remainders / divisivility

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by GmatKiss » Sun May 27, 2012 12:11 am
paonie wrote:If n is a positive integer what is the remainder when 3^(8n+3) is divided by 5?

A)7
B)5
C)2
D)1
E)0

Please help!! THX!!! :)
powers of 3 follow the pattern:

3
9
7
1
3
9
7
1
.
.
.

sub:for n in the given

say n=1 we need to find the value of 3^11
say n=2 we need to find the value of 3^19

In both cases, it will end with 7

Reminder when 7 is divided by 5 is 2

IMO: C
Last edited by GmatKiss on Sun May 27, 2012 12:13 am, edited 1 time in total.
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Legendary Member
Posts: 2789
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Location: Chennai, India
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by GmatKiss » Sun May 27, 2012 12:12 am
Here is another DS question, testing the same,

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

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


IMO: C
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