6 hours
11am to 12 is 1 hour 12 to 5pm is 5 hours → 11am to 5pm is 1 + 5 = 6 hours
6 17:00 hours minus 11:00 hours = 6:00 hours
72 hours
48 hours.
From 6am to 5pm is 11 hours.
6:15am to 5pm is 10 hours and 45 minutes.
There are 4*(1 + 6*k) hours where k is an integer.
48
2 hours
8.5 hours
9 hours.