The remainder when 1+3+3^2+3^3+..........+3^200 is divided by 13 is
A.12
B.7
C.0
D.5
E.3
A detailed explanation will be appreciated.
A.12
B.7
C.0
D.5
E.3
A detailed explanation will be appreciated.
I hink the answer should be 0. (C). This is how I did it, although there may be a better way!
1+3+9+27+81+..3^200.
Take the terms in groups of 3 numbers
first group 1+3+9=13. divisible by 13.
Next group.
27+81+243 = 27(1+3+9), divisible by 13.
Since there are 201 numbers in the sequence, 201/3 = 67 groups.
Each of these groups is divisible by 13. So remainder is 0.
Whats the OA.
