Question

Из пункта А вниз по реке отправился плот. через 1 часнавстречу ему из пенкта В находящегося на расстоянии 30 км от А вышла моторная лодка которая встретилась с плотом через 2 часа после своего выхода. Найдите собственную скорость лодки если скорость течения реки 2 км в час

Answer 1

Пусть скорость плота будет 2 км/ч, а время 1+2=3 ч, расстояние 2*3=6 км. 
Тогда скорость лодки равна (х-2), время 2 ч, расстояние 2(х-2). Общее расстояние 30 км. По условию задачи составим уравнение:

6+(х-2)*2=30
2х-4=30-6
2х=28
х=14
Ответ: 14 км\ч собственная скорость лодки.

Answer 2

Problem Analysis

We are given the following information: - A raft started from point A and traveled downstream for 1 hour. - After 1 hour, a motorboat started from point B, which is 30 km away from point A, and met the raft after 2 hours.

We need to find the speed of the motorboat, given that the river current is flowing at a speed of 2 km/h.

Solution

Let's assume the speed of the raft is R km/h and the speed of the motorboat is M km/h.

When the raft travels downstream for 1 hour, it covers a distance of R km.

When the motorboat starts from point B, it has to cover a distance of 30 km to meet the raft. The time taken by the motorboat to cover this distance is 2 hours.

During this time, the raft has also traveled downstream for 2 hours. The distance covered by the raft in 2 hours is 2R km.

Since the motorboat and the raft meet each other, the total distance covered by both of them is equal to the distance between point A and point B, which is 30 km.

So, we can write the equation: R + 2R = 30

Simplifying the equation, we get: 3R = 30

Dividing both sides by 3, we find: R = 10

Therefore, the speed of the raft is 10 km/h.

Now, let's calculate the speed of the motorboat.

The speed of the motorboat is the sum of its own speed and the speed of the river current. So, we can write the equation: M + 2 = 10 + 2

Simplifying the equation, we get: M + 2 = 12

Subtracting 2 from both sides, we find: M = 10

Therefore, the speed of the motorboat is 10 km/h.

Answer

The speed of the motorboat is 10 km/h.

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