Question

Лодка шла против течения 6 часов и по течению реки 4 часа. Насти скорость лодки в стоячей воде, если она прошла всего 66 км, а скорость течения реки равна 2 км/ч

Answer 1

Ответ:

Объяснение:

скорость в стоячей воде равна х. скорость по течению х+2 ,а против течения х-2

пишем уравнение пути

(х-2)*6+(х+2)*4=66

6х-12+4х+8=66

10х=70

х=7 км/час скорость в стоячей воде

Answer 2

Problem Analysis

We are given the following information: - The boat traveled against the current for 6 hours. - The boat traveled with the current for 4 hours. - The total distance traveled by the boat is 66 km. - The speed of the river current is 2 km/h.

We need to determine the speed of the boat in still water.

Solution

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

When the boat is traveling against the current, its effective speed is reduced by the speed of the current. So, the boat's speed against the current is (x - 2) km/h.

When the boat is traveling with the current, its effective speed is increased by the speed of the current. So, the boat's speed with the current is (x + 2) km/h.

We can use the formula distance = speed × time to calculate the distances traveled in each case.

The distance traveled against the current is (x - 2) × 6 km.

The distance traveled with the current is (x + 2) × 4 km.

According to the given information, the total distance traveled by the boat is 66 km. So, we can write the equation:

(x - 2) × 6 + (x + 2) × 4 = 66

Now, let's solve this equation to find the value of x.

Calculation

Expanding the equation, we get:

6x - 12 + 4x + 8 = 66

Combining like terms, we have:

10x - 4 = 66

Adding 4 to both sides of the equation, we get:

10x = 70

Dividing both sides of the equation by 10, we get:

x = 7

Answer

The speed of the boat in still water is 7 km/h.

Please let me know if I can help you with anything else.