That's nine and one quarter hours.
10 hours and 15 minutes.
2 hours and 30 minutes.
6 and 3/4.
It is (8.5 + 24k) hours where k is an integer.
13:45 + 24n hours where n is any integer.
1275
4:00 am
The interval 10:10 am to 5:00 pm is 6 hours and fifty minutes long.
From 10:30 to 12:00 there are 1 1/2 hoursFrom 12:00 to 5:00 pm there are 5 hoursTotal 6 1/2 hours
From 7:45 AM to 1:15 PM is a total of 5 hours and 30 minutes. To break it down, there are 5 hours from 7:45 AM to 12:45 PM, plus an additional 30 minutes to reach 1:15 PM.
From 7:45 AM to 2:20 PM is a total of 6 hours and 35 minutes. To break it down, there are 6 hours from 7:45 AM to 1:45 PM, and then an additional 35 minutes from 1:45 PM to 2:20 PM.
From 7:45 AM to 6:15 PM is a total of 10 hours and 30 minutes. To break it down, there are 10 hours from 7:45 AM to 5:45 PM, and then an additional 30 minutes from 5:45 PM to 6:15 PM.