Question

двигаясь против течения реки теплоход за 3 часа прошёл расстояние в 75 км Найди скорость течения реки если собственная скорость теплохода 30 км/ч​

Answer 1

Ответ: 5 км/час

Пошаговое объяснение:

Скорость теплохода против течения равна:

V=S/t=75/3=25км/час

Скорость теплохода против течения состоит из разности собственной скорости и скорости течения реки:

V=Vc-Vр

Отсюда скорость течения реки  равна:

Vр=V-Vc=30-25=5км/час

Answer 2

Ответ:

75-30=45км

Скорость реки 45км

Answer 3

Problem Analysis

We are given that a boat is moving against the current of a river and it takes 3 hours to travel a distance of 75 km. We need to find the speed of the river current.

Solution

Let's assume the speed of the boat in still water is x km/h and the speed of the river current is y km/h.

When the boat is moving against the current, its effective speed is reduced by the speed of the current. Therefore, the boat's speed against the current is (x - y) km/h.

We are given that the boat takes 3 hours to travel a distance of 75 km. We can use the formula distance = speed × time to write the equation:

75 = (x - y) × 3

Now, we can solve this equation to find the value of y, which represents the speed of the river current.

Calculation

Let's solve the equation:

75 = (x - y) × 3

Dividing both sides of the equation by 3:

25 = x - y

Rearranging the equation to isolate y:

y = x - 25

We are also given that the speed of the boat in still water is 30 km/h. Substituting this value into the equation:

y = 30 - 25

Simplifying the equation:

y = 5

Answer

The speed of the river current is 5 km/h.

Explanation

When the boat is moving against the current, its effective speed is reduced by the speed of the current. In this case, the boat's speed in still water is 30 km/h, and the speed of the river current is 5 km/h. Therefore, when the boat is moving against the current, its speed is reduced to 25 km/h (30 km/h - 5 km/h). This reduced speed allows the boat to travel a distance of 75 km in 3 hours.