Combinatorics
Source: Greece Archimedes Junior 2019
March 16, 2020
combinatorics
Problem Statement
In the table are written the positive integers . John and Mary have the ability to make together the following move:
They select two of the written numbers in the table, let and they replace them with the numbers and .
John claims that after a finite number of such moves, it is possible to triple all the numbers in the table, e.g. have the numbers: . Mary thinks a while and replies that this is not possible. Who of them is right?