Answer:
6 hours and 20 minutes
Step-by-step explanation:
5:15 to 6:15 ( 1 hour ) 6:15 to 7:15 ( 2 hours) 7:15 to 8:15 ( 3 hours) 8:15 to 9:15 ( 4 hours) 9:15 to 10:15 ( 5 hours) 10:15 to 11:15 ( 6 hours)
but she left at 11:35 leaving 20 minutes remaining. so, 6 hours and 20 minutes.