7 hours 45 minutes
13 hours and 15 minutes.
10 hrs
2:55 pm
6 hours 30 minutes
6 hours and 30 minutes.
8 and 1/2
(8.25 + 24k) hours, where k is any integer.
7
10.5 + 24*k hours where k is any integer.
6:15am to 5pm is 10 hours and 45 minutes.
It is 9.5+24*n hours where n is an integer.
That would be 1215 pm, as the East Coast is three hours ahead of the West Coast.