Six hours in total !
48
There are 5 hours between 4 pm and 9 pm
There are 2+12k hours where k is an integer.
5 hours and 30 minutes.
12 hours
The duration between 3:30 pm and 9:15 pm is 5 hours and 45 minutes.
Twenty hours.
5 hours
5 hours
5 hours
8 hours