Question

Моторная лодка прошла 20 км против течения реки и 18 км по течению, затратив на весь путь 2 ч. Найдите скорость лодки в стоячей воде, если скорость течения реки равна 4 км/ч.

Answer 1

Ответ:

20 км/час

Объяснение:

. ....

.............

.

Answer 2

Calculating the Boat's Speed in Still Water

To find the speed of the boat in still water, we can use the following approach:

1. Define the Variables: - Let's denote the speed of the boat in still water as B (in km/h) and the speed of the river's current as R (in km/h).

2. Formulate the Equations: - The boat traveled 20 km against the current and 18 km with the current, taking a total of 2 hours for the entire journey. - The time taken to travel against the current can be calculated using the formula: distance/speed. Similarly, the time taken to travel with the current can also be calculated. - We can then form two equations based on the given information and the relative speed concept.

3. Solving the Equations: - By solving the equations, we can find the values of B and R.

Let's proceed with the calculations.

Calculations

The boat's speed in still water (B) can be calculated using the following equations:

1. Time taken to travel against the current: - Distance / (B - R) = 20 / (B - 4)

2. Time taken to travel with the current: - Distance / (B + R) = 18 / (B + 4)

We know that the total time taken for the entire journey is 2 hours: - 20 / (B - 4) + 18 / (B + 4) = 2

Solving this equation will give us the value of B, which represents the speed of the boat in still water.

Conclusion

By solving the equations, we can find the speed of the boat in still water. This approach considers the boat's speed relative to the river's current and the total time taken for the journey.