MathDB
Soccer tournament and arrangement in arithmetical progession

Source: Balkan MO ShortList 2010 C1

April 5, 2020

Problem Statement

In a soccer tournament each team plays exactly one game with all others. The winner gets 33 points, the loser gets 00 and each team gets 11 point in case of a draw. It is known that nn teams (n3n \geq 3) participated in the tournament and the final classification is given by the arithmetical progression of the points, the last team having only 1 point.
[*] Prove that this configuration is unattainable when n=12n=12 [*] Find all values of nn and all configurations when this is possible