A woman drives a car from one city to another with different constant speeds along the trip. She drives at a speed of 50.0 km/h for 20.0 min, 85.0 km/h for 25.0 min, makes a stop for 30.0 min, then continues at 45.0 km/h for 35.0 min, at which point she reaches her destination.
(a) What is the total distance between her starting point and destination (in km)?
(b) What is the average speed for the entire trip (in units of km/h)?