Part A: 20.9
First, note that there are 2+3+1+4+1=11 players. We add their ages. So 19+19+20+20+20+21+22+22+22+22+23 = 230.
Therefore, the mean age is 230/11 = 20.9090, rounded to 20.9.
Part B: 34
When we get one more member, the player count goes to 12. The mean goes to 22. So 22*12 is the sum of all the player's ages, which is 264. We already know 230 for the 11 original players, so the new player must be 264-230 = 34 years old.
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