7.5 hours.
8 hrs 30 min
8:30 to 5 is 8 and 1/2 hours no matter what you do for lunch.
5 minutes and 15 seconds.
0 hours are in 20 min an hour is 60 min
8 hours, 20 minutes
610 min / 60 = 10.167 hours.
2 hours
5 hours, 50 minutes
60 min = 1 hour so 375 min = 6 hours 15 minutes.
320 min = 51/3 hours = 5hours 20minutes
5.5 hours.