Problem #PRU-100409-3

Problems Algebra and arithmetic Word problems Tables and tournaments Chessboards and chess pieces

Problem

On the way back from his weekly maths circle Harry created the following puzzle:

Put 48 rooks on a 10×10 board so that each rook attacks only 2 or 4 empty cells.

When he showed this problem to the teachers next Saturday they were very impressed and decided to include it in the next problem set. Try to find a suitable placement of rooks.