The length of the road from point A to point B is 48 km. If a motorcyclist increases his speed by 12 km / h

| May 21, 2021 | education

The length of the road from point A to point B is 48 km. If a motorcyclist increases his speed by 12 km / h, then in 2 hours he will travel more than 48 km. If he reduces the speed by 3 km / h, which even in 4 hours will not have time to reach point B. What is the speed of the motorcyclist?

A motorcyclist will cover a distance of 48 km in 2 hours if he travels at a speed of 24 km / h:
48/2 = 24.
We get this if the motorcyclist increases the speed by 12 km, that is,
24 – 12 = 12 km / h.
According to the condition, it is known that in 2 hours he will travel more than 48 km. This means that the motorcyclist’s speed is more than 12 km / h. Suppose 13 km / h:
12 + 1 = 13 (km / h) – the speed of the motorcyclist.
13 – 3 = 10 (km / h) – if this speed is reduced by 3 km / h.
10 * 4 = 40 (km) – a motorcyclist will travel in 4 hours at a speed of 10 km / h.
That is, at a speed of 10 km / h, the motorcyclist will not reach point B, which corresponds to the condition. This means that the speed of the motorcyclist is 13 km / h.
Answer: 13 km / h.



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