A car travels up a hill at a constant speed of 56 km/h and returns down the hill at a constant speed of 34 km/h. calculate the average speed for the round trip.
Imagine the trip to be 476 km. The trip up takes 476/56, or 8.5 hours. The trip down takes 476/34, or 14 hours. All told, the sum is 476*2/8.5+14, or 42.31 km/h average. ☺☺☺☺
