MathDB
A meeting and break

Source: Problem 1, Polish NO 1989

August 17, 2005
modular arithmeticcombinatorics proposedcombinatorics

Problem Statement

An even number of politicians are sitting at a round table. After a break, they come back and sit down again in arbitrary places. Show that there must be two people with the same number of people sitting between them as before the break.. Additional problem: Solve the problem when the number of people is in a form 6k+36k+3.