Christmas Contest - Team Round - Problem 12

Johnny arrives at a Carnival at 0:00 with 4 tickets. Each hour starting at 1:00, he collects a ticket. At 1:31 he spends one ticket. At 3:01 he spends two tickets. At 4:31 he spends three tickets, and so on: every one and a half hour after 1:31, he spends one more ticket than an hour and a half ago.

At what time does Johnny not have enough tickets to continue this pattern? Express your answer as a time, with the colon removed (so if your answer was 5:43, input 543).