There are 4 hours between 8:30 am and 12:30 pm.
There are 4 + 24*k hours where k is an integer.
Nine hours.
There are 6 hours and 30 minutes from 8-1230pm to 230pm.
1960
8 hours.
Nine and a half hours.
840
4.5 hours
That is eight hours.
There are 4 and 1/2 hours between 8:30 and 1.
ten and a half
If those two times are both in the same day, then the period between them is 121/2 hours long.
8:30am to noon is 3.5 hours.