distances of 10 centers in 8x8 board of unit squares
Source: Mexican Mathematical Olympiad 1999 OMM P4
July 28, 2018
combinatorial geometrydistanceboardcombinatorics
Problem Statement
An board is divided into unit squares. Ten of these squares have their centers marked. Prove that either there exist two marked points on the distance at most , or there is a point on the distance from the edge of the board.