2
Part of 2020 OMpD
Problems(2)
3 bodybuilders fighting against a n-headed monster
Source: 2020 1st OMpD L3 P2 - Brazil - Olimpíada Matemáticos por Diversão
7/8/2023
Metadieu, Tercieu and Quartieu are three bodybuilder warriors who fight against an -headed monster. Each of them can attack the monster according to the following rules:(1) Metadieu's attack consists of cutting off half of the monster's heads, then cutting off one more head. If the monster's number of heads is odd, Metadieu cannot attack;(2) Tercieu's attack consists of cutting off a third of the monster's heads, then cutting off two more heads. If the monster's number of heads is not a multiple of 3, Tercieu cannot attack;(3) Quartieu's attack consists of cutting off a quarter of the monster's heads, then cutting off three more heads. If the monster's number of heads is not a multiple of 4, Quartieu cannot attack;If none of the three warriors can attack the monster at some point, then it will devour our three heroes. The objective of the three warriors is to defeat the monster, and for that they need to cut off all its heads, one warrior attacking at a time.For what positive integer values of is it possible for the three warriors to combine a sequence of attacks in order to defeat the monster?
combinatoricsnumber theory
Game with powers of 4
Source: 2020 1st OMpD L2 P2 - Brazil - Olimpíada Matemáticos por Diversão
7/8/2023
A pile of stones is given. Arnaldo and Bernaldo play the following game: In each move, it is allowed to remove (any power of ) stones from the pile. They make their moves alternately, and the player who can no longer play loses. If Arnaldo is the first to play, who has the winning strategy?
combinatoricsPerfect Powersgame strategyGame Theory