Assuming that you mean 8:30 and not 8.30 (which is actually 8:18), there are (8.5 + 24k) hours, where k is any integer.
It is five hours.
5 hrs, 15 mins
From 8:30 AM to 5:00 PM is a total of 8 hours and 30 minutes. This can be calculated by counting the hours from 8:30 AM to 5:00 PM, which is 8 hours, plus the additional 30 minutes.
8
Six hours in total !
It is five hours.
5 hrs, 15 mins
8:30 to 5 is 8 and 1/2 hours no matter what you do for lunch.
From 8:30 AM to 5:00 PM is a total of 8 hours and 30 minutes. This can be calculated by counting the hours from 8:30 AM to 5:00 PM, which is 8 hours, plus the additional 30 minutes.
From 5:30 P.M. on Wednesday to 8:30 A.M. on the following Monday is 111 hours.
8
There are 15 hours and 15 minutes between 5:15 am and 8:30 pm.
Six hours in total !
48
There are 5 hours between 4 pm and 9 pm
5 hours and 30 minutes.
There are 2+12k hours where k is an integer.