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1989 All Soviet Union Mathematical Olympiad
491
491
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1989 All Soviet Union Mathematical Olympiad
Problems
(1)
ASU 491 All Soviet Union MO 1989 8 pawns on a cheesbooard
Source:
8/13/2019
Eight pawns are placed on a chessboard, so that there is one in each row and column. Show that an even number of the pawns are on black squares.
combinatorics
Chessboard