Respuesta :

5 hours + 4 hours = 9 hours
30 minutes + 45 minutes =75 minutes
60 minutes in an hour, so 75 minutes =1 hour and 15 minutes, or 1.25 hours
9 hours + 1.25 hours =10.25 hours or 10 hours and 15 minutes. 
9 hours and 15 minutes. 5+4=9, 45+30= 75, 75-60= 15