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## Homework Statement

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

## Homework Equations

## 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.

Thanks,

Ron.