Q. Ten persons numbered 1,2,⋯,10 play a chess tournament, each player playing against every other exactly one game. It is known that no game ends in a draw. Let w1,w2,....,w10 are the number of games won by players 1,2,3,⋯,10, respectively, and l1,l2,⋯,l10 are the number of games lost by the players 1,2,⋯,10, respectively, then,