The speed of the boat along the river is 17 km / h and against the current 11 km / h. What is the speed of the river?

Let’s solve the problem algebraically.

Let’s introduce the variable V km / h – the speed of the river flow.

Imagine the boat’s own speed from numerical data:

17 – V km / h, the case when the boat is moving down, that is, downstream.
11 + V km / h, the case when the boat is moving up, that is, against the current.
Let’s make the equation:

11 + V = 17 – V;

2V = 17-11;

V = 6: 2;

V = 3.

Let’s solve the problem arithmetically.

What is the doubled current speed: 17 – 11 = 6 km / h.
What is the speed of the current: 6: 2 = 3 km / h.
Answer: The river flows 3 kilometers per hour at such a speed.