Question

Расстояние между 2-ми портами равно 504 км. двигаясь против течения реки, теплоход проходит это расстояние за 21час. за сколько часов он проидет это расстояние по течению реки, если скорость течения равна 2км/ч?

Answer 1

1) 504÷21=24 (км/час) - скорость теплохода против течения
2) 24+4=28(км\час) - скоростьтеплохода
3) 504÷28=18(час)-время теплохода, когда он плывет по течению

Answer 2

1) 504:21=24 (км/ч) - скорость теплохода против течения2) 24+2=26 (км/ч) - собственная скорость теплохода3) 26+2=28 (км/ч) - скорость теплохода по течению4) 504:28=18 (часов) - время, за которое теплоход пойдет это расстояние по течению реки

Answer 3

Calculation of Time to Travel Distance Against the Current

To calculate the time it takes for the boat to travel a distance of 504 km against the current, we need to consider the speed of the boat and the speed of the current.

Let's assume the speed of the boat is x km/h and the speed of the current is 2 km/h.

The boat is traveling against the current, so its effective speed will be the difference between the boat's speed and the current's speed.

Therefore, the effective speed of the boat against the current is (x - 2) km/h.

We know that the boat takes 21 hours to travel a distance of 504 km against the current.

Using the formula distance = speed × time, we can set up the equation:

504 km = (x - 2) km/h × 21 hours

Now, let's solve for x to find the speed of the boat.

504 km = 21 hours × (x - 2) km/h

Dividing both sides of the equation by 21:

24 km = x - 2

Adding 2 to both sides of the equation:

x = 26 km/h

Therefore, the speed of the boat is 26 km/h when traveling against the current.

Calculation of Time to Travel Distance with the Current

Now, let's calculate the time it takes for the boat to travel the same distance of 504 km with the current.

Since the boat is now traveling with the current, its effective speed will be the sum of the boat's speed and the current's speed.

Therefore, the effective speed of the boat with the current is (x + 2) km/h.

To calculate the time, we can use the same formula:

504 km = (x + 2) km/h × t hours

We need to solve for t, the time it takes for the boat to travel the distance with the current.

504 km = (26 km/h + 2 km/h) × t hours

504 km = 28 km/h × t hours

Dividing both sides of the equation by 28:

t = 504 km / 28 km/h

t ≈ 18 hours

Therefore, it will take approximately 18 hours for the boat to travel a distance of 504 km with the current.

Summary

To summarize, the boat takes 21 hours to travel a distance of 504 km against the current, with a speed of 26 km/h. On the other hand, it takes approximately 18 hours to travel the same distance with the current, with a speed of 28 km/h.

Please note that these calculations are based on the given information and assumptions made about the speed of the boat and the current.