A bus departs station X and travels straight to station Y, which is 90km due north of X, in 2h. It halts at Y for 30min and then returns directly to X along the same road in 1h30min.
(a) Calculate the total distance travelled and the total time taken, including the halt.
(b) Determine the average speed for the whole trip.
(c) Determine the average velocity for the whole trip.
(d) Explain why the magnitudes of the average speed and average velocity are different or the same for this journey.