Here you will find a weekly problem to work on. If you submit a full solution, you will be eligible to receive a $5 coffee giftcard. Winners will be randomly selected every two weeks.
Include your Baruch Student ID in the file to check eligibility. Solutions must be handwritten and scanned.
Suppose you have a 2022x2018 chessboard with its square tiles painted black and white alternatingly. Some square tiles have pebbles on them, so that the total number of pebbles in each row and the total number of pebbles on each column are always odd numbers (a single square tile may have more than one pebble). Show that the number of pebbles on black squares must be an even number.