The car traveled three quarters of the way at a speed of 20 m / s, and the rest

The car traveled three quarters of the way at a speed of 20 m / s, and the rest at a speed of 10 m / s. What is the average speed along the way?

Initial data: S1 (length of the first part of the path) = 3/4 S, V1 (speed on the first part of the path) = 20 m / s; S2 (length of the second part of the path) = 1/4 S; V2 (speed on the second part of the path) = 10 m / s.

Let’s compose a formula for finding the average vehicle speed: Vav = S / t = S / (S1 / V1 + S2 / V2) = S / (3/4 S / V1 + 1/4 S / V2) = 1 / (3 / 4V1 + 1 / 4V2).

Let’s calculate: Vav = 1 / (3 / (4 * 20) + 1 / (4 * 10)) = 1 / 0.0625 = 16 m / s.

Answer: The average speed of the vehicle along the entire route is 16 m / s.