From 8:30 AM to 12:00 AM (midnight) is a total of 15.5 hours. This is calculated by counting the hours from 8:30 AM to 12:00 PM (3.5 hours) and then adding the 12 hours from 12:00 PM to 12:00 AM.
8 hours.
12am to 4pm is 16 hours.
Nine hours.
840
Nine and a half hours.
4.5 hours
ten and a half
24
It is (8.5 + 24k) hours where k is an integer.
8:30am to noon is 3.5 hours.
12 hours
8 hours and 30 minutes.