A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 15.0 min at 65.0 km/h, 20.0 min at 75.0 km/h and 60.0 min at 40.0 km/h, and spends 15.0 min eating lunch and buying gas.
Determine the average speed for the trip.
Average Speed = total distance/total time
The Attempt at a Solution
(65+75+80)/(15+20+60+15)=1.64 which isn't logical. I don't understand how to compute the total distance???