Question

Рыболов отправившись на рыбалку на моторной лодке затратил на путь по течению реки 2 целых одна треть часа на обратный путь на 28 минут Больше Найдите скорость течения реки если скорость лодки в стоячей воде равна 16,5 километров в час

Answer 1

Сфоткай ка или учебник взяли

Answer 2

Calculation of River Current Speed

To find the speed of the river current, we can use the given information about the time taken for the downstream and upstream journeys of the fisherman.

Let's denote the speed of the river current as x (in kilometers per hour) and the speed of the boat in still water as y (in kilometers per hour).

The fisherman took 2 hours and 1/3 hour (or 7/3 hours) for the downstream journey, and 28 minutes (or 28/60 hours) longer for the upstream journey.

For the downstream journey, the effective speed of the boat is the sum of the speed of the boat in still water and the speed of the river current, which is y + x.

For the upstream journey, the effective speed of the boat is the difference between the speed of the boat in still water and the speed of the river current, which is y - x.

We can set up the following equations based on the given information:

Downstream journey: (y + x) × (7/3) = d (where d is the distance traveled downstream)

Upstream journey: (y - x) × (7/3 + 28/60) = d (where d is the same distance traveled upstream)

To find the speed of the river current (x), we can solve these equations simultaneously.

Let's substitute the given values into the equations:

Downstream journey: (y + x) × (7/3) = d

Upstream journey: (y - x) × (7/3 + 28/60) = d

Now, let's solve these equations:

(y + x) × (7/3) = (y - x) × (7/3 + 28/60)

Simplifying the equation:

7(y + x) = (y - x) × (7 + 28/60)

7y + 7x = (y - x) × (7 + 28/60)

7y + 7x = (y - x) × (7 + 7/15)

7y + 7x = (y - x) × (112/15)

Now, let's solve for x:

7y + 7x = 112y/15 - 112x/15

7x + 112x/15 = 112y/15 - 7y

(105x + 112x)/15 = 105y/15

217x/15 = 105y/15

217x = 105y

x = (105y)/217

Given that the speed of the boat in still water (y) is 16.5 kilometers per hour, we can substitute this value into the equation to find the speed of the river current (x):

x = (105 × 16.5)/217

Calculating the value of x:

x ≈ 8 kilometers per hour

Therefore, the speed of the river current is approximately 8 kilometers per hour.