Question

Автомобиль из А в В ехал со средней скоростью 50 км/ч., а обратно возвращался со скоростью 30 км/ч. Какова его средняя скорость?

Answer 1

По моему 40 км/ч должно быть правельно

Answer 2

40км/ч так как среднее число между 50 и 30 число 40!

Answer 3

Calculation of Average Speed

To calculate the average speed of a round trip, we need to consider the distances traveled and the time taken in each direction. In this case, the car traveled from point A to point B at a speed of 50 km/h and returned from point B to point A at a speed of 30 km/h.

Let's denote the distance from A to B as d. Since the car traveled at a speed of 50 km/h, the time taken to travel from A to B can be calculated using the formula:

Time taken from A to B = Distance / Speed = d / 50 Similarly, the time taken to return from B to A can be calculated using the formula:

Time taken from B to A = Distance / Speed = d / 30 The total time taken for the round trip is the sum of the time taken from A to B and the time taken from B to A:

Total time taken = (d / 50) + (d / 30)

To calculate the average speed, we divide the total distance traveled (2d) by the total time taken:

Average speed = Total distance / Total time taken = 2d / [(d / 50) + (d / 30)]

Simplifying the equation further:

Average speed = 2d / [(3d + 5d) / (1500)] = 2d * (1500 / 8d) = 375 km/h

Therefore, the average speed of the car for the round trip is 375 km/h.

Please note that the above calculation assumes that the car traveled the same distance from A to B and from B to A.

Conclusion

The average speed of the car for the round trip from point A to point B and back, with a speed of 50 km/h in one direction and 30 km/h in the other direction, is 375 km/h.

Let me know if there's anything else I can help with!