Question

От пристани A до пристани B, расстояние между которыми 10 км, вниз по течению реки отправился плот. через некоторое время за ним отправился катер, который догнал плот через 15 мин и тут же, не меняя скорости, повернул обратно. Известно, что плот причалил к пристани B на 54 мин позже, чем катер к пристани A. Найдите собственную скорость катера и время движения плота до момента начала движения катера от пристани A, если скорость течения реки 2 км/ч, а собственная скорость движения катера больше 10 км/ч. должно получиться: 1 ч 20 мин; 12 км/ч. в интернете я ничего не нашла( помогите пожалуйста​

Answer 1

Ответ:

см фофото

Объяснение:

Answer 2

Problem Analysis

We are given the following information: - The distance between two ports, A and B, is 10 km. - A raft starts downstream from port A. - After some time, a motorboat starts from port A and catches up with the raft in 15 minutes. - The motorboat immediately turns back without changing its speed. - The raft arrives at port B 54 minutes later than the motorboat arrives at port A. - The speed of the river current is 2 km/h. - The speed of the motorboat is greater than 10 km/h.

We need to find the speed of the motorboat and the time it takes for the raft to reach the point where the motorboat started.

Solution

Let's assume the speed of the motorboat is v km/h.

To solve this problem, we can use the formula: distance = speed × time.

Let's calculate the time it takes for the motorboat to catch up with the raft.

The distance traveled by the motorboat in 15 minutes is (v - 2) × (15/60) km, and the distance traveled by the raft in the same time is 2 × (15/60) km.

Since the motorboat catches up with the raft, the distance traveled by both is the same. Therefore, we can write the equation:

(v - 2) × (15/60) = 2 × (15/60)

Simplifying the equation, we get:

(v - 2) = 2

Solving for v, we find:

v = 4 km/h

Now, let's calculate the time it takes for the raft to reach the point where the motorboat started.

The distance between the starting point of the raft and the point where the motorboat started is 10 km. The speed of the raft is the sum of the speed of the river current and the speed of the motorboat, which is 2 + 4 = 6 km/h.

Let's use the formula distance = speed × time to find the time it takes for the raft to travel 10 km:

10 = 6 × time

Solving for time, we find:

time = 10/6 = 1 hour and 40 minutes = 1 hour 40 minutes

Therefore, the speed of the motorboat is 4 km/h and the time it takes for the raft to reach the point where the motorboat started is 1 hour and 40 minutes.

Answer

The speed of the motorboat is 4 km/h and the time it takes for the raft to reach the point where the motorboat started is 1 hour and 40 minutes.

Note: The answer provided is based on the given information and calculations.