I would like to have this question answered neatly. Thanks :)

Question 3. (6+4 points) a): Consider a betting game with multiple rounds. Let X1- be the amount a player wins or looses on the 15th round of the game. Then X1,X2,X3, are independent and identically distributed (IID) random variables with probability distribution: P(X3- = 2) = i, 13(er = U) = %, P(X = 2) = i. Let 5'20 = 2321 X; be the total amount of money won in 20 rounds. Calculate approximately P(S