For problems that human teams eventually get correct, they seem to have submitted mostly 1 time -- occasionally 2 or 3. For problems that they did not get correct, there are some problems with up to 16 submissions.

The way the rules work is that you can submit as often as you want. Team with the most solved problem wins. The time it took to solve all the problems is the tiebreaker.

But submitting a non-working solution gives you a time penalty (usually 20 mins). Yet this time penalty only applies if in the end, you actually solve the problem. So it never hurts to try.