You roll a fair die. Let Sn be the sum of the first n tosses. what is the probability of having Sn divisible by 5 ?
a) n is infinite
The Attempt at a Solution
there are also cases that n is finite, but I believe if I know how the infinite case works, I will be able to figure out the finite case.
I managed to solve it by using the counting method for n=2 and n=3... but couldn't find a real solution with some pattern.
Would appreciate any help.