You can eliminate two options here: 1:18PM and 2:03PM.
This leaves two options.
Combining the time it takes to hike to the top and hiking back down, it should take 5h 7m.
That would not be possible at 11:15AM, which leaves one possible answer.
8:41 AM.
Checking if it's correct, you can add 5 hours and 7 minutes to 8:41 AM and it will be 1:48 PM.