In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.
You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?