The motor ship passed 81.49 km along the river and 11362 km upstream, the own speed of the motor

The motor ship passed 81.49 km along the river and 11362 km upstream, the own speed of the motor ship is 26.4 km / h and the current speed is 1.7. how long did the ship go

It is likely that the distance traveled against the current was 113.62 km.
We find the speed of the ship in both directions:
26.4 + 1.7 = 28.1 (km / h) – downstream;
26.4 – 1.7 = 24.7 (km / h) – upstream.
The velocities are found, the distances are known by the condition of the problem, we find the time of movement in each direction:
81.49 / 28.1 = 2.9 (hours) – downstream;
113.62 / 24.7 = 4.6 (hours) – upstream.
The total travel time is:
2.9 + 4.6 = 7.5 (hours).
Answer: the ship was on the way for 7.5 hours.