Question

Моторная лодка прошла против течения реки 300 км и вернулась в пункт отправления затратив на обратный путь на 5:00 меньше чем на путь против течения Найдите скорость лодки в неподвижной воде если скорость течения реки равна 5 км ч

Answer 1

1)300*(1:х-5)-1:(х+5)=5
10:(х2-25)=1/60
х2=625
х=25км/ч
ответ:25км/ч

Answer 2

1) 300*(1:х-5)-1:(х+5)=5
10:(х2-25)=1/60
х2=625
х=25 км/ч.
Ответ:25км/ч

Answer 3

Problem Analysis

We are given that a motorboat traveled 300 km against the current of a river and then returned to the starting point, spending 5 hours less on the return journey than on the journey against the current. We need to find the speed of the boat in still water, given that the speed of the river current is 5 km/h.

Solution

Let's assume the speed of the boat in still water is x km/h. Since the boat is traveling against the current on the first leg of the journey, its effective speed will be (x - 5) km/h. On the return journey, the boat is traveling with the current, so its effective speed will be (x + 5) km/h.

We are given that the boat took 5 hours less on the return journey than on the journey against the current. This means that the time taken on the return journey is 5 hours less than the time taken on the first leg of the journey.

Let's calculate the time taken for each leg of the journey:

- Time taken on the first leg of the journey (against the current): 300 / (x - 5) hours - Time taken on the return journey (with the current): 300 / (x + 5) hours

According to the given information, the time taken on the return journey is 5 hours less than the time taken on the first leg of the journey. So we can write the equation:

300 / (x + 5) = 300 / (x - 5) - 5

To solve this equation, we can cross-multiply and simplify:

300(x - 5) = 300(x + 5) - 5(x - 5)

Simplifying further:

300x - 1500 = 300x + 1500 - 5x + 25

Simplifying again:

300x - 1500 = 300x + 1500 - 5x + 25

The 300x terms cancel out, and we are left with:

-1500 = 1500 - 5x + 25

Simplifying further:

-1500 = 1525 - 5x

Rearranging the equation:

5x = 1525 + 1500

5x = 3025

x = 605

Therefore, the speed of the boat in still water is 605 km/h.

Answer

The speed of the boat in still water is 605 km/h.