Question

Расстояние между пристанями А и В по реке ровно 36км. Из А в В отплыл плот, а Из В в А спустя 8часов отошла лодка. В пункты назначения они прибыли одновременно. Какова скорость плота, если собственная скорость лодки 12 км/ч?

Answer 1

1)36/12=3(час) столько плыла лодка
2)8+3=11(час) столько плыл плот
3) 36/11=3,27
Ответ: 3,27км/час скорость плота.

Answer 2

Problem Analysis

We are given that the distance between two river docks, A and B, is 36 km. A raft departs from dock A towards dock B, while a boat departs from dock B towards dock A after 8 hours. Both the raft and the boat arrive at their destinations simultaneously. We need to determine the speed of the raft, given that the boat's speed is 12 km/h.

Solution

Let's assume the speed of the raft is x km/h. Since the raft and the boat arrive at their destinations simultaneously, we can set up the following equation based on the time and distance traveled:

Distance traveled by the raft = Distance traveled by the boat

The distance traveled by the raft can be calculated as 36 km, as it travels the entire distance between the docks. The distance traveled by the boat can be calculated as the product of its speed (12 km/h) and the time it takes to travel from dock B to dock A, which is 8 hours.

Therefore, we can write the equation as:

36 km = 12 km/h * 8 hours

Now, let's solve this equation to find the speed of the raft.

Calculation

To find the speed of the raft, we can rearrange the equation as follows:

36 km = 12 km/h * 8 hours

Dividing both sides of the equation by 8 hours:

36 km / 8 hours = 12 km/h

Simplifying:

4.5 km/h = 12 km/h

Therefore, the speed of the raft is 4.5 km/h.

Answer

The speed of the raft is 4.5 km/h.

Verification

To verify the answer, we can substitute the calculated speed of the raft into the equation and check if it holds true:

36 km = 4.5 km/h * 8 hours

Simplifying:

36 km = 36 km

The equation holds true, which confirms that the calculated speed of the raft is correct.