pieces on a 10x10 board
Source: XII May Olympiad (Olimpiada de Mayo) 2006 L1 P5
September 22, 2022
combinatorics
Problem Statement
In some squares of a board, a piece is placed in such a way that the following property is satisfied: For each square that has a piece, the number of pieces placed in the same row must be greater than or equal to the number of pieces placed in the same column. How many tiles can there be on the board? Give all chances.