A person travels by car from one city to another with dissimilar constant speeds between pairs of cities. She drives for 30mins at 80 km/h, 12 min at 100 km/h, and 45 min at 40 km/h and spends 15 min eating lunch and buying gas. (a) Decide the average speed for the trip (b) Decide the distance among the initial and final cities along the route.