If he starts at 8:00 AM and you start counting up by 1 hour at a time...
8:00 - 9:00 = 1 hour
9:00 - 10:00 = 1 hour
10:00 - 11:00 = 1 hour
11:00 - 12:00 = 1 hour
So far that is 4 hours that have passed and we are up to 12:00. Now remember, when we reach 12:00 we switch from AM to PM (that's 12 noon).
We only have 49 minutes left so now we just add that in
12:49 PM is when he crossed the finish line.
