A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 20.0 min at 85.0 km/h, 20.0 min at 75.0 km/h, and 50.0 min at 55.0 km/h and spends 55.0 min eating lunch and buying gas. (a) Determine the average speed for the trip.
A) Average speed:
a) 65.7 km/h
b) 70.3 km/h
c) 75.6 km/h
d) 80.2 km/h