The boat covered 14 km upstream and 11 km upstream in 1 hour. Find your own speed if the current is 3 km / h.

Let the boat’s own speed be x km / h, then: x + 3 (km / h) speed of the boat along the river; x – 3 (km / h) speed of the boat against the river flow;
14 / (x + 3) (h) – time spent on the way along the river; 11 / (x – 3) (h) – the time spent on the path against the stream of the river. Knowing that the whole journey took 1 hour, we make the equation: 14 / (x + 3) + 11 / (x – 3) = 1; x ^ 2 – 24 ∙ x = 0; x = 24 (km / h).
Answer: the boat’s own speed was 24 km / h.