The speed of the river is 2.2 km / h. The boat’s own speed is 15.4 km / h. What way did the boat go upstream in 3.5 hours?

Let’s solve this task by actions:

1. Let’s find the speed of the boat itself, which is sailing against the stream of the river: 15.4 – 2.2 = 13.2 (kilometer / hour).

2. Now we find the mileage of the boat against the river for 3.5 hours: 13.2 * 3.5 = 46.2 (kilometers).

Answer: the boat sailed along the course of the river for 46.2 kilometers.