Average Speed Calculation for Round Trip

What is the average speed for a car that moves uphill at 57.9 km/h and then back downhill at 50.4 km/h for the round trip?

The average speed for the round trip is approximately 53.5 km/h

The average speed for the round trip is calculated by taking the total distance traveled and dividing it by the total time taken. In this case, since the car returns to its starting point, the total distance traveled is twice the distance traveled uphill (or downhill).

Let's assume that the car traveled uphill for a distance d at a speed of 57.9 km/h. The time taken for this part of the trip is t1 = d/57.9.

On the return trip, the car traveled downhill for the same distance d at a speed of 50.4 km/h. The time taken for this part of the trip is t2 = d/50.4.

The total distance traveled is 2d, and the total time taken is t1 + t2. Therefore, the average speed for the round trip is:

average speed = total distance / total time

              = 2d / (t1 + t2)

              = 2d / (d/57.9 + d/50.4)

              = 2 / (1/57.9 + 1/50.4)

              ≈ 53.5 km/h

By using this calculation method, we can determine the average speed of the car for the round trip. For further information on average speed, you can refer to reliable sources or academic materials.