Contestants get 4.5 hours for each of the two days of competition. They have to solve three problems in that time, so on average you can spend 1.5 hours per problem (if you're aiming to finish all three).
That said, the gap from "can't do it at all" to "can do it in 60 hours" is probably quite a bit larger than the gap from 60 hours to 1.5 hours.
