We know that she stopped a 8:05, we want to know when did she start, so we have to go like back in time to see that. So if we go to 7:55, 10 minutes have passed, if we go to 7:45, 20 minutes have passed and that's the time she started to jump.
7:45 This is because there are 60 minutes in an hour and if you have 45 minutes (7:45) and you subtract 60-45 that equals 15, and plus the 5 you have at 8:05
