Question

По реке бумажная лодочка проплывёт со скоростью 4 1/2 км/ч. В ручье её скорость была бы в двое меньше. Какова скорость течения воды в ручье?

Answer 1

Решение: 4,5:2=2,25(км/ч)-V воды в ручье

Answer 2

Calculation of the River Current Speed

To determine the speed of the river current, we can use the information provided in the question. Let's break down the problem step by step:

1. The speed of the paper boat in still water is given as 4 1/2 km/h. 2. The speed of the paper boat in the stream would be half of its speed in still water.

To find the speed of the river current, we need to calculate the difference between the speed of the paper boat in still water and its speed in the stream.

Let's denote the speed of the river current as x km/h.

The speed of the paper boat in the stream can be calculated as follows:

Speed in the stream = Speed in still water - Speed of the river current

Using the given information, we can set up the equation:

4 1/2 - x = 2 1/4

To solve this equation, we need to convert the mixed numbers to improper fractions:

9/2 - x = 9/4

Now, let's solve for x:

9/2 - x = 9/4

To eliminate the fractions, we can multiply both sides of the equation by the least common denominator (LCD), which is 4:

4 * (9/2 - x) = 4 * (9/4)

Simplifying the equation:

18 - 4x = 9

Now, let's isolate x by moving the constant term to the other side:

-4x = 9 - 18

-4x = -9

Finally, divide both sides of the equation by -4 to solve for x:

x = -9 / -4

Simplifying the fraction:

x = 9/4

Therefore, the speed of the river current is 9/4 km/h.

Please note that the negative sign in the equation was canceled out during the simplification process.

Answer

The speed of the river current in the stream is 9/4 km/h.