1

Part of 1971 Poland - Second Round

Problems(1)

k squares in a n x n chessboard

Source: Polish MO Second Round 1971 p1

In how many ways can you choose

k

squares on a chessboard

n \times n

k \leq n

) so that no two of the chosen squares lie in the same row or column?

combinatoricscombinatorial geometryChessboard