Question

Среднее арифметическое скоростей по течению и против течения лодки равно 8,5 км/ч. Скорость лодки по течению реки 10,9 км/ч. Чему равна скорость течения реки? Какова скорость течения реки? Какова скорость лодки против течения реки?

Answer 1

Х - скорость течения 
у - скорость лодки
х+у  - скорость по течению
у-х  - скорость против течения
среднее арифметическое (х+у)+(у-х)/2 = 8,5
х+у +у-х = 17
2у = 17
у = 17/2
у = 8,5 км/ч  - скорость лодки

х+у  = 10,9 
х + 8,5 = 10,9
х =  10,9-8,5
х = 2,4 км/ч - скорость течения 
8,5 -2,4 = 6,1 км/ч скорость лодки против течения

Answer 2

Calculation of River Current Speed and Boat Speed

To find the speed of the river current and the speed of the boat against the current, we can use the given information. Let's denote the speed of the river current as x km/h and the speed of the boat in still water as y km/h.

According to the problem, the average speed of the boat when traveling with the current and against the current is 8.5 km/h. Additionally, the speed of the boat when traveling with the current is 10.9 km/h.

Using this information, we can set up the following equations:

1. Average speed of the boat when traveling with the current and against the current: - (y + x) / 2 = 8.5 km/h 2. Speed of the boat when traveling with the current: - y + x = 10.9 km/h We can solve these equations to find the values of x and y.

Solving the Equations

To solve the equations, we can use substitution or elimination. Let's use the substitution method.

From equation 2, we can express y in terms of x: - y = 10.9 - x

Substituting this value of y into equation 1, we get: - (10.9 - x + x) / 2 = 8.5

Simplifying the equation: - (10.9 + x - x) / 2 = 8.5 - 10.9 / 2 = 8.5 - 5.45 = 8.5

This equation is not true, which means there is no solution that satisfies both equations. Therefore, there might be an error in the given information or the problem statement.

Unfortunately, we cannot determine the speed of the river current or the speed of the boat against the current with the given information. It is not possible to calculate the values based on the provided data.

If you have any additional information or if there is anything else I can assist you with, please let me know!