numbers in a circle
Source: 2022 Centroamerican and Caribbean Mathematical Olympiad, P2
December 1, 2022
combinatoricsalgebra
Problem Statement
Ana, Beto, Carlos, Diana, Elena and Fabian are in a circle, located in that order. Ana, Beto, Carlos, Diana, Elena and Fabian each have a piece of paper, where are written the real numbers respectively.
At the end of each minute, all the people simultaneously replace the number on their paper by the sum of three numbers; the number that was at the beginning of the minute on his paper and on the papers of his two neighbors. At the end of the minute replacements have been made and each person have in his paper it´s initial number. Find all the posible values of . If at the beginning of the minute Ana, Beto, Carlos have the numbers , respectively, then at the end of the minute , Beto is going to have the number .