Answer:
Gregor started his hike at 5:45 AM.
Step-by-step explanation:
To find this answer you have to first take away 15 from 7:30 which equals 7:15, then you need to take away 1 hour which equals 6:15. Finally, you need to take away 30 minutes which equals 5:45 AM. Which is the time that he started his hike.