Solution to Puzzle 1. To attack the
maximum possible number of vacant cells two chess queens should be
placed in the center of the chessboard as shown in Solution A. In this
case 42 vacant cells are under attack.
Solution to Puzzle 2. To attack the minimum possible number of
empty squares two chess queens should be placed in any of the four
corners of the chessboard in two adjacent squares - as shown in
Solution B. In this case total number of vacant cells under attack is