Question

Собственная сколюрость теплохода 18 километров в час . двигаясь 2 часа по озеру и 3 часа по реке , катер прошёл 84 километра . Какова скорость течения реки ?

Answer 1

Найдем расстояние по озеру. 2ч*18=36км (на озере течения нет, скорость движения по озеру равна собственной скорости теплохода).
Найдем оставшееся кол-во км. 84-36=48. Теперь найдем скорость по реке. 48:3 = 16. Собственная скорость катера - 18км/ч. Следовательно, скорость течения = 18-16=2.

Answer 2

18 * 2 = 36 км прошел по озеру 
 84 - 36 = 48 км прошел по реке
 48 : 3 = 16 км/ч скорость по реке

18 - 16 = 2 км/ч скорость течения реки

Answer 3

Calculation of River Current Speed

To calculate the speed of the river current, we can use the formula:

Distance = Speed x Time

Let's denote the speed of the boat in still water as x (in kilometers per hour) and the speed of the river current as y (in kilometers per hour).

Given the following information:

- The boat traveled at a speed of 18 kilometers per hour for 2 hours on the lake. - The boat traveled at a speed of 18 kilometers per hour + the speed of the river current for 3 hours on the river. - The total distance traveled by the boat is 84 kilometers.

We can set up the following equations:

Equation 1: 2x = 18 * 2 (since the boat traveled at a speed of 18 kilometers per hour for 2 hours on the lake)

Equation 2: 3(x + y) = 18 * 3 (since the boat traveled at a speed of 18 kilometers per hour + the speed of the river current for 3 hours on the river)

Equation 3: 2x + 3(x + y) = 84 (since the total distance traveled by the boat is 84 kilometers)

Let's solve these equations to find the speed of the river current.

Solving the Equations

Equation 1: 2x = 18 * 2

Simplifying Equation 1, we get:

2x = 36

Dividing both sides by 2, we find:

x = 18

Equation 2: 3(x + y) = 18 * 3

Simplifying Equation 2, we get:

3x + 3y = 54

Equation 3: 2x + 3(x + y) = 84

Substituting the value of x from Equation 1 into Equation 3, we get:

2 * 18 + 3(18 + y) = 84

Simplifying Equation 3, we get:

36 + 54 + 3y = 84

Combining like terms, we have:

90 + 3y = 84

Subtracting 90 from both sides, we find:

3y = -6

Dividing both sides by 3, we get:

y = -2

Answer

The speed of the river current is -2 kilometers per hour.

Please note that the negative sign indicates that the river is flowing in the opposite direction of the boat's motion.