The boat passed against the course of the river 21.6 km in 1.2 hours, and along the course

The boat passed against the course of the river 21.6 km in 1.2 hours, and along the course of the river in the same time, the distance was 4.8 km longer. What is the speed of the boat and the speed of the river?

Way upstream – 21.6 km;

Way with the flow? 4.8 km more;

Time downstream = upstream – 1.2 hours;

Own speed -? km / h;

Current speed -? km / h.

Solution:

1) 21.6 + 4.8 = 26.4 (km) – distance downstream;

2) 21.6 / 1.2 = 18 (km / h) – upstream speed;

3) 26.4 / 1.2 = 22 (km / h) – downstream speed;

4) 22 – 18 = 4 (km / h) – twice the current speed;

5) 4/2 = 2 (km / h) – river flow speed;

6) 18 + 2 = 20 (km / h) – own speed of the boat.

Answer: 2 km / h and 20 km / h.