The speed of the motor boat downstream is 7 times the speed of the river.

The speed of the motor boat downstream is 7 times the speed of the river. Find the speed of the river if it travels 28.8 km in 2 hours of movement along the lake?

In order to solve this problem, it is necessary to draw up an equation.
Let x km / h be the speed of the river, then 7x km / h is the speed of the boat. Since we know that the boat, moving downstream for two hours, sailed 28.8 kilometers, we have the equation:
28.8 = (x + 7x) * 2;
(The equation is based on the distance formula, which equals the product of speed and time);
Reduce the resulting equation by two:
14.4 = x + 7x;
14.4 = 8x;
x = 1.8 km / h – river flow speed;
Answer: 1.8 km / h.