The car covered the first part of the journey (30 km) at an average speed of 15 m / s.

The car covered the first part of the journey (30 km) at an average speed of 15 m / s. He covered the remaining 40 km in 1 hour. How fast was the car moving all the way?

Average vehicle speed:

Vav. = S / t, where S is the total distance traveled (S = S1 + S2), t is the total travel time (t = t1 + t2).

The first part of the path:

S1 = 30 km = 30,000 m, V1 = 15 m / s, t1 = S1 / V1.

Second part of the path:

S2 = 40 km = 40,000 m, t2 = 1 h = 3600 s.

Formula:

Vav. = (S1 + S2) / (S1 / V1 + t2).

Let’s perform the calculation:

Vav. = (30,000 + 40,000) / (30,000 / 15 + 3600) = 70,000 / 5600 = 12.5 m / s or 45 km / h.

Answer: The car was moving all the way at an average speed of 12.5 m / s (45 km / h).