1st and 2nd try: 30 sec – 1 min per problem. 3rd try: 2 min plus 1 – 3 min per problem. You can't submit before the minimum time, and your answers are submitted automatically when time runs out.
After the 1st try you see which problems are wrong. After that you only see your score. You get up to 3 tries.
3rd try is your hint chance: every problem gets a hint and a mini lesson.