ten and a half
840
8 hours.
4.5 hours
Nine and a half hours.
Nine hours.
6 hours from 4pm to 10pm
3pm to 10pm is 7 hours.
It is (8.5 + 24k) hours where k is an integer.
8:30am to noon is 3.5 hours.
8 hours and 30 minutes.
1960
14 + 24k where k is any integer.