12 1 Affendy, Ben, Cheong and Derrick sold some tickets for a charity carnival. Affendy sold of the total number of tickets. Ben, Cheong and Derrick sold the remaining tickets in the ratio of 4: 3:9. Derrick sold 1315 more tickets than Ben. (a) (b) (c) How many tickets did Ben sell? What was the total number of tickets sold by Ben, Cheong and Derrick? How many tickets did the four boys sell altogether?​