KöMaL 2017 B4911
We have placed chessmen on a chessboard. There is an odd number of chessmen standing in every row, and in every column. Prove that the total number of chessmen on the black fields of the chessboard is even.
Official text KöMaL. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.
Similar problems
These problems have the most words in common with this statement.