The car traveled the distance between the two cities at a speed of 60 km / h. She returned back at half the speed.
| March 15, 2021 | education
The car traveled the distance between the two cities at a speed of 60 km / h. She returned back at half the speed. Find the average speed.
Initial data: V1 (vehicle speed when driving between two cities) = 60 km / h; V2 (vehicle speed on the way back) = V1 / 2 = 30 km / h; S1 = S2 (distance between cities) = 0.5S (total distance traveled).
The average speed of the machine is determined by the formula: Vav. = S / t = S / (S1 / V1 + S2 / V2) = S / (S / 2V1 + S / 2V2) = 1 / (1 / 2V1 + 1 / 2V2).
Calculation: Vav. = 1 / (1 / (2 * 60) + 1 / (2 * 30)) = 40 km / h.
Answer: The average speed of the car is 40 km / h.
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