Problem #WSP-5474

Descriptions Invariants

Problem

Four black dots are drawn on a whiteboard. We write the numbers \(10,20,30,\) and \(40\) on top the dots and then play the following game: choose any of the four dots, subtract three from the number written on it, and then add one to the number written on top of each of the three other dots. After playing this game for some number of steps, can we make all four dots have the number \(25\) on top of them?