A driver covers a certain distance by car driving at 60 km/hr and returns back to the starting point riding on a scooter at 20 km/hr. What was the average speed for the whole journey?	Choices
A) 24 km/h B) 26 km/h C) 28 km/h D) 30 km/h E) 32 km/h
time 1 = d / 60   time 2 = d / 20   total time = d/60 + d/20 = 4d/60 = d/15   average speed = total distance / total time = 2d / (d/15) = 30 km/h   The answer is 30 km/h.
<result>D</result>
A driver covers a certain distance by car driving at 60 km/hr and returns back to the starting point riding on a scooter at 20 km/hr. What was the average speed for the whole journey?