Let p be a prime. Let S be a set of (p-1) integers, none of which are divisible by p. Show that some subset of S has a sum that has a remainder of 1 when divided by p.

(The sum of a set is defined as the sum of the elements of the set)

(In reply to answer? by Solomon)

Pretend that some adversary (not you) picks the prime and the set S. 

Posted by David Shin on 2004-12-29 21:35:15