2:30 hours from 9:30pm to midnight, then 8:30 hours from midnight to 8:30am. Total is 2:30 + 8:30 = 11:00 so answer is 11 hours. Alternatively 9:30pm to 9:30am is 12 hours, then minus 1 hour to get to 8:30am, so 12 - 1 = 11 also.
934
8 hours.
2.5 + 5.5 = 8.0eight hours
Nine hours.
840
Nine and a half hours.
4.5 hours
ten and a half
8:30am to noon is 3.5 hours.
It is (8.5 + 24k) hours where k is an integer.
13:45 + 24n hours where n is any integer.
8 hours and 30 minutes.