It is (8.5 + 24k) hours where k is an integer.
From 8:30 AM to 12:00 PM is 3 hours and 30 minutes. From 12:45 PM to 5:00 PM is 4 hours and 15 minutes. Adding these together, the total time is 7 hours and 45 minutes.
8 hours.
10 hours and 15 minutes.
2 hours and 30 minutes.
Nine hours.
840
Nine and a half hours.
4.5 hours
That's nine and one quarter hours.
ten and a half
8:30am to noon is 3.5 hours.
8 hours and 30 minutes.