Question

Моторная лодка, двигаясь против течения реки, проплыла расстояние от турбазы до города за 3 часа, а обратный путь за 2 часа 15 минут. Скорость течения реки 4км/ч. Какова собственная скорость лодки?

Answer 1

3*(х-4)=2,25*(х+4)
x*0,75=9+12
x=28 км/час - скорость лодки

Answer 2

Calculation of the Boat's Speed

To calculate the boat's speed, we need to consider the time taken for the boat to travel from the tourist base to the city and back, as well as the speed of the river's current.

Let's denote the boat's speed as B and the speed of the river's current as C.

Given the following information: - The boat took 3 hours to travel from the tourist base to the city. - The boat took 2 hours and 15 minutes (or 2.25 hours) to travel from the city back to the tourist base. - The speed of the river's current is 4 km/h.

We can use the formula: Distance = Speed x Time to calculate the distance traveled by the boat.

Calculation of the Distance Traveled

Let's denote the distance from the tourist base to the city as D.

Using the formula, we can calculate the distance traveled by the boat from the tourist base to the city: D = (B - C) x 3.

Similarly, we can calculate the distance traveled by the boat from the city back to the tourist base: D = (B + C) x 2.25.

Since the distance traveled in both directions is the same, we can equate the two equations: (B - C) x 3 = (B + C) x 2.25.

Simplifying the equation, we get: 3B - 3C = 2.25B + 2.25C.

Calculation of the Boat's Speed

Now, let's solve the equation to find the boat's speed (B).

3B - 2.25B = 3C + 2.25C.

Simplifying further, we get: 0.75B = 5.25C.

Dividing both sides of the equation by 0.75, we find: B = 7C.

Therefore, the boat's speed (B) is 7 times the speed of the river's current (C).

Conclusion

In conclusion, the boat's speed is 7 times the speed of the river's current.