The speed of the boat against the river flow is 17.8 km / h, and its own speed. boats – 19.4 km / h.

The speed of the boat against the river flow is 17.8 km / h, and its own speed. boats – 19.4 km / h. Find the speed of the boat along the river.

Let’s solve this task by actions with explanations:
1) 19.4 – 17.8 = 1.6 kilometers per hour – the speed of the river flow, since the speed of the boat against the river is 17.8 kilometers per hour, and the boat’s own speed is 19.4 kilometers per hour;
2) 19.4 + 1.6 = 21 kilometers per hour – the speed of the boat along the river.
Answer: 21 kilometers per hour.