Fruits in a box
Source: Lusophon Mathematical Olympiad 2022 Problem 2
November 3, 2022
combinatoricsGame Theory
Problem Statement
Anselmo and Claudio are playing alternatively a game with fruits in a box. The box initially has fruits. Anselmo plays first and each turn consists of taking away , or fruits from the box or taking away of the fruits from the box (this is only possible when the number of the fruits left in the box is a multiple of ). The player that takes away the last fruit from the box wins. Which of these two players has a winning strategy? How should that player play in order to win?