If they left town at 9:00 AM, and then drove for 4 hours and 35 minutes, we need to add the time taken to the starting time to find the time they arrived at the gas station.
9:00 AM + 4 hours and 35 minutes = 1:35 PM
Therefore, they arrived at the gas station at 1:37 PM, which means they left town at 9:00 AM.