ASU 076 All Russian MO 1966 shortest path on cross-lined paper
Source:
June 19, 2019
algebra
Problem Statement
A rectangle is drawn on the cross-lined paper with its sides laying on the lines, and is times more than ( is an integer). All the shortest paths from to coming along the lines are considered. Prove that the number of those with the first link on is times more then of those with the first link on .