7 and a half hours
If they're both on the same date, then they mark a period of 21/2 hours.
8 1/2 hours, if the times are on the same day.
3 pm is 15 hours, so 15-3 1/2 = 11 1/2 hours or 11:30 hours
(11.5 + 24k) hours where k is an integer. 11 and 1/2 hours.
2 hours
2 hours.
7 and a half hours
Two answers, depending on whether am or pm times Examples: 6:30am to 2pm = 7:30 hours 6:30pm to 2pm = 19:30 hours and so on ...
There are 4 hours from 10 am to 2 pm.
2 hours
9 am to 12 pm: 3 hours 12 pm to 2:30 pm: 2 1/2 hours 3 + 2 1/2 = 5 1/2 hours. So there are 5 1/2 hours between 9 am and 2:30 pm.
There are 2+12k hours where k is an integer.