Bundeswettbewerb Mathematik 1975 Problem 1.4
Source: Bundeswettbewerb Mathematik 1975 Round 1
October 22, 2022
combinatoricsgraphcycle
Problem Statement
In the country of Sikinia there are finitely many cities. From each city, exactly three roads go out and each road goes to another Sikinian city. A tourist starts a trip from city and drives according to the following rule: he turns left at the first city, then right at the next city, and so on, alternately. Show that he will eventually return to