The motor ship goes downstream of the river at a speed of 23.1 km / h, and against the stream 18.8 km / h

The motor ship goes downstream of the river at a speed of 23.1 km / h, and against the stream 18.8 km / h. Find your own boat speed.

1. We take for x (km / h) the speed of a river vessel in still water, for y (km / h) speed

river flow:

2. Let’s compose two equations:

(1) x + y = 23.1;

(2) x – y = 18.8;

3. Add these equations:

2x = 41.9;

x = 20.95 km / h.

Answer: the speed of a river vessel in still water is 20.95 km / h.