MathDB

99

Part of 1990 IMO Longlists

Problems(1)

Unit squares with the same color - ILL 1990 USS2

Source:

9/19/2010
Given a 10×1010 \times 10 chessboard colored as black-and-white alternately. Prove that for any 4646 unit squares without common edges, there are at least 3030 unit squares with the same color.
combinatorics unsolvedcombinatorics