The car drove the first 4 km in 12 minutes, and then for 20 minutes

The car drove the first 4 km in 12 minutes, and then for 20 minutes and moved at a speed of 54 km / h. determine the average speed of movement

Initial data: S1 (first section of the route) = 4 km, t1 (time of passing the first section) = 12 minutes = 12/60 h = 0.2 h, V2 (speed on the second section) = 54 km / h, t2 (time passing the second section) = 20 minutes = 20/60 hours = 1/3 hours.

Equation for calculation:

Vav. = S / t = (S1 + S2) / (t1 + t2) = (S1 + V2 * t2) / (t1 + t2).

Let’s do the calculation:

Vav. = (4 + 54/3) / (0.2 + 1/3) = 41.25 km / h.

Answer: The average speed is 41.25 km / h.