Question

Prove that for any set of integers, there is a subset of them whose sum is divisible by n.

Answer 1

Is n an arbitrary integer?

Answer 2

yes, i can be... but I think I figure it out... I know the Pigeonhole Principle can be applied here... after I'm finish i'll write the answer (to see if I am correct).

Answer 3

As you've written it, the result is false. For example A = {17} is a set of integers. The only n for which a sum of members of A is divisible by n is 1 and 17.