Get acquainted in a competition
Source: Indonesia Mathematics Olympiad 2005 Day 2 Problem 8
June 2, 2008
combinatorics proposedcombinatorics
Problem Statement
There are contestants in a mathematics competition. Each contestant gets acquainted with at least other contestants. One of the contestants, Amin, state that at least four contestants have the same number of new friends. Prove or disprove his statement.