The average age of a football team of 9 players is 29 years. If 3 more players are included in the team the average becomes 28 years, then the average age  (in years) of the three included players is?

25

Average age of 9 players = 29

Total age of 9 players = 29 x 9

Average age of 12 players = 28

Total age of 12 players = 28 x 12 = (29 - 1) x 12 = (29 x 12) - 12

So,

Total age of 3 new players = Total age of 12 players - Total age of 9 players

= (29 x 12) - 12 - (29 x 9)

= (29 x 3) - 12

= 87 - 12 = 75

Hence, Avg. age = \(\frac{75}{3}\) = 25