9.8

Part of 2000 All-Russian Olympiad Regional Round

Problems(1)

bw cells in 200x200 table - All-Russian MO 2000 Regional (R4) 9.8

Source:

The cells of the

200 \times 200

table are painted black and white so that there are

404

more black cells than white ones. Prove that there is a

2 \times 2

square in which the number of white cells is odd.

combinatoricsColoring