A car travels from point A to B at 60km/hr and from point B to A at 90km/hr. What is the average speed of the car?

Question: A car travels from point A to B at 60km/hr and from point B to A at 90km/hr. What is the average speed of the car?Solution: Let the distance from A to B be x,time of first travel = x/60 hrtime of second travel = x/90 hraverage = 2x/{(x/60) + (x/90)}= 72km/hr