Question

Екскурсійний катер пройшов за течією річки 12 км і повернувся назад, витративши на подорож год.Знайдіть власну швидкість катера, якщо швидкість течії річки дорівнює 2 км/год.​

Answer 1

Ответ:

21дробь20

Объяснение:

вычислить 20+1дробь20

Answer 2

To find the speed of the boat, we can use the formula:

Speed of boat = Distance / Time

In this case, the boat traveled a distance of 12 km downstream and then returned upstream. Let's break down the problem into two parts:

1. Downstream journey: - Distance = 12 km - Speed of the river current = 2 km/h - Let's assume the speed of the boat is x km/h during the downstream journey.

During the downstream journey, the boat's speed is the sum of its own speed and the speed of the river current. Therefore, the effective speed of the boat is (x + 2) km/h.

Using the formula, we can calculate the time taken for the downstream journey:

Time = Distance / Speed = 12 / (x + 2) hours

2. Upstream journey: - Distance = 12 km - Speed of the river current = 2 km/h - Let's assume the speed of the boat is x km/h during the upstream journey.

During the upstream journey, the boat's speed is the difference between its own speed and the speed of the river current. Therefore, the effective speed of the boat is (x - 2) km/h.

Using the formula, we can calculate the time taken for the upstream journey:

Time = Distance / Speed = 12 / (x - 2) hours

Now, let's consider the total time taken for the entire trip. The boat traveled downstream for a certain time, then returned upstream for the same amount of time. The total time taken is given as 1 hour.

Therefore, we can set up the equation:

(12 / (x + 2)) + (12 / (x - 2)) = 1

To solve this equation, we can multiply through by (x + 2)(x - 2) to eliminate the denominators:

12(x - 2) + 12(x + 2) = (x + 2)(x - 2)

Simplifying the equation:

12x - 24 + 12x + 24 = x^2 - 4

24x = x^2 - 4

x^2 - 24x - 4 = 0

Now, we can solve this quadratic equation to find the value of x.