The motor boat went along the river at a speed of 16 km / h, and against the current at a speed of 14 km / h.

The motor boat went along the river at a speed of 16 km / h, and against the current at a speed of 14 km / h. Find the speed of the river.

To solve this problem, we introduce two conditional variables “X” and “Y”, through which we denote the speed of the motor boat and the speed of the river, respectively.
Then, based on the data of the problem, we compose the following equations:
1) X + Y = 16;
2) X – Y = 14.
Solving a system of two equations with two unknowns, we get X = 16 – Y.
Substituting X into the second equation, we get 16 – Y – Y = 14 or 2Y = 2 or Y = 1 kilometer per hour.
Answer: the speed of the river is 1 kilometer per hour.