From 9:30 pm to 12:00 am is 2.5 hours, then from 12:00 am to 7:00 am is 7 hours. Therefore, the total hours from 9:30 pm to 7:30 am is 2.5 + 7 = 9.5 hours.
12 hours
4 hours and 15 minutes.
9 hours.
7
6
This is equivalent to 16 hours.
Ten hours.
8 hours.
9h 15m
10 hours and 15 minutes.
10 hours and 45 minutes.
12 hours 30 minutes.
There are (7.5 + 24k) hours where k is an integer.