The speed of the boat is 17 km / h downstream and 11 km / h upstream. What is the speed of the river?

Let the speed of the river flow be x km / h. Then the boat’s own speed is equal to 17 – х km / h or 11 + х km / h. We get the following equation:

17 – x \ u003d 11 + x, we transfer from x to one, without x to the other side, while changing the sign of the numbers that we transfer to the opposite.

– x – x = 11 – 17;

-2x = -6 | : (-2), divide both sides of the equation by -2.

x = 3 (km / h) – river flow speed.

Answer: 3 km / h.