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? 1) Какова скрость течения реки? 2) Какова скорость лодки против теч. реки?

Answer 1

Given Information:

- The average speed of the boat in still water is 8.5 km/h. - The speed of the boat downstream (with the current) is 10.9 km/h.

Calculating the Speed of the River Current:

To find the speed of the river current, we can use the following formula:

Speed of the boat upstream = (Speed of the boat in still water) - (Speed of the river current)

Since the average speed of the boat in still water is 8.5 km/h and the speed of the boat downstream is 10.9 km/h, we can calculate the speed of the river current as follows:

Speed of the river current = Speed of the boat in still water - Speed of the boat downstream

Speed of the river current = 8.5 km/h - 10.9 km/h

Speed of the river current = -2.4 km/h

Therefore, the speed of the river current is -2.4 km/h.

Answering the Questions:

1) The speed of the river current is -2.4 km/h.2) To calculate the speed of the boat against the current, we can use the following formula:

Speed of the boat upstream = (Speed of the boat in still water) - (Speed of the river current)

Substituting the given values, we have:

Speed of the boat upstream = 8.5 km/h - (-2.4 km/h)

Speed of the boat upstream = 8.5 km/h + 2.4 km/h

Speed of the boat upstream = 10.9 km/h

Therefore, the speed of the boat against the current is 10.9 km/h. Note: The negative sign for the speed of the river current indicates that the current is flowing in the opposite direction of the boat's motion.