The car drove 400 km. It is known that the first half of the entire time of movement, he moved at a speed of 90 km / h

| June 1, 2021 | education

The car drove 400 km. It is known that the first half of the entire time of movement, he moved at a speed of 90 km / h, and the second half of the time traveled 175 km. What was the speed of the car on the second section of the road?

S = 400 km.

t1 = t2 = t / 2.

V1 = 90 km / h.

S2 = 175 km.

V2 -?

To find the speed of the vehicle on the second section V2, it is necessary to divide the length of the second section S2 by the time it passes t2: V2 = S2 / t2.

Let’s find the length of the first section of the path S1 by the formula: S1 = S – S2.

Let us express the travel time of the first section of the path t1 by the formula: t1 = S1 / V1 = (S – S2) / V1.

Since t1 = t2 = t / 2 by the problem statement, then V2 = S2 * V1 / (S – S2).

V2 = 175 km * 90 km / h / (400 km – 175 km) = 70 km / h.

Answer: the car drove the second half of the time at a speed of V2 = 70 km / h.



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