"Mean score of 6 games is 15. The mean game of 7 games is 16. How many points were score in the seventh game?"
6 games: 15 = N/6 N = 6*15
7 games; 16 = (N+s)/7 where s is score in seventh game, so N + s = 7*16
Hence 6*15 + s = 7*16
s = 7*16 - 6*15 = 22
