1-round chess tournament involves 10 players from 2 countries
Source: Tuymaada Junior 2007 p6
May 12, 2019
combinatorics
Problem Statement
One-round chess tournament involves players from two countries. For a victory, one point is given, for a draw - half a point, for defeat - zero. All players scored a different number of points. Prove that one of the chess players scored in meetings with his countrymen less points, than meeting with players from another country.