The boat along the river in 7 hours covered the same distance as it did in 8 hours against the current.

The boat along the river in 7 hours covered the same distance as it did in 8 hours against the current. What is the flow of the river even if the speed of the boat is 30 m / h.

1. Take the speed of the water flow in the river as x.

2. The speed of the river vessel in the direction of the water flow in the river (30 + x) km / h, its speed against the flow of water in the river (30 – x) km / h.

3. Let’s compose the equation:

8 (30 – x) = 7 (30 + x);

240 – 8x = 210 + 7x;

15x = 30;

x = 2 km / h.

Answer: the speed of the water flow in the river is 2 km / h.