The motorcyclist was driving at a speed of 100 km / h for the first half of the time, and at a speed of 80 km / h the

| June 25, 2021 | education

The motorcyclist was driving at a speed of 100 km / h for the first half of the time, and at a speed of 80 km / h the second. Determine the average speed of the motorcyclist on the entire road.

Given:

v1 = 100 km / h – the speed of the motorcyclist in the first half of the driving time;

v2 = 80 km / h – the speed of the motorcyclist in the second half of the driving time.

It is required to determine the average speed of the motorcyclist v (km / h).

Let t be the total travel time of the motorcyclist.

Then, in the first half of the time, the motorcyclist traveled a distance equal to:

S1 = v1 * t / 2 = 100 * t / 2 = 50 * t.

In the second half of the time, the motorcyclist traveled a distance equal to:

S2 = v2 * t / 2 = 80 * t / 2 = 40 * t.

Total motorcyclist drove:

S = S1 + S2 = 50 * t + 40 * t = 90 * t.

Then the average speed is:

v = S / t = 90 * t / t = 90 km / h.

Answer: The average speed of a motorcyclist is 90 kilometers per hour.



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