Solve the given parts of following problem:
Problem: A woman drives a car from one city to another with different constant speeds along the trip. She drives at a speed of 70.0 km/h for 15.0 min, 90.0 km/h for 20.0 min, makes a stop for50.0 min, and then continues at 40.0 km/h for 30.0 min, at which point she reaches her destination.
Part A: What is the total distance between her starting point and destination (in km)?
Part B: What is the average speed for the entire trip (in units of km/h)?
Please show me how work it out above problem.