Question

Мотоциклист и велосипедист одновременно отправились из пункта A в пункт B , расстояние между которыми 90 км. Скорость велосипедиста 10км / ч, а скорость мотоциклиста 45км / ч. Ровно на середине дороги мотоцикл заглох , и дальше мотоциклист шел пеком со скоростью 3км/ч . через сколько часов после начала движения велосипедист догонит мотоциклиста?

Answer 1

Полдороги это 45 км
45/45(скорость)=1час
за час велосипедист проехал 10 км 
расстояние между ними 45-10=35км
35/(10-3)=5ч
ну как то так

Answer 2

Problem Analysis

We have a motorcyclist and a cyclist traveling from point A to point B, a distance of 90 km. The cyclist's speed is 10 km/h, while the motorcyclist's speed is 45 km/h. The motorcycle breaks down halfway through the journey and the motorcyclist continues on foot at a speed of 3 km/h. We need to determine how many hours after the start of the journey the cyclist will catch up to the motorcyclist.

Solution

To solve this problem, we can use the concept of relative speed. The relative speed between the cyclist and the motorcyclist is the difference between their speeds. In this case, the relative speed is 45 km/h - 10 km/h = 35 km/h.

Since the motorcyclist travels at a speed of 45 km/h for the first half of the journey and then walks at a speed of 3 km/h for the second half, we can calculate the time it takes for the motorcyclist to complete the journey. Let's call this time "t".

The time it takes for the motorcyclist to travel the first half of the journey is given by the formula: time = distance / speed For the first half of the journey, the distance is 90 km / 2 = 45 km, and the speed is 45 km/h. Therefore, the time taken for the first half of the journey is: t1 = 45 km / 45 km/h = 1 hour

The time it takes for the motorcyclist to travel the second half of the journey is given by the formula: time = distance / speed For the second half of the journey, the distance is also 45 km, but the speed is 3 km/h. Therefore, the time taken for the second half of the journey is: t2 = 45 km / 3 km/h = 15 hours

The total time taken by the motorcyclist to complete the journey is the sum of t1 and t2: t = t1 + t2 = 1 hour + 15 hours = 16 hours

Now, we can calculate the distance traveled by the cyclist in 16 hours at a speed of 10 km/h: distance = speed * time distance = 10 km/h * 16 hours = 160 km

Since the distance between point A and point B is 90 km, the cyclist will catch up to the motorcyclist after traveling a distance of 90 km. Therefore, the cyclist will catch up to the motorcyclist after: time = distance / speed time = 90 km / 10 km/h = 9 hours

Answer

The cyclist will catch up to the motorcyclist after 9 hours.

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