Her travel time to her destination can be found by dividing 50km by 40km/h to get 1.25 hours or 1 hour 15 minutes. He travel time home can be found by dividing 50km by 60km/h to get 0.83 hours or. 50 minutes. The total time was 2.083 hours or 2 hours and 5 minutes. So here average speed is 100 divided by 2.083 hours = 48 miles per hour.