The train travels the distance between the two cities 6 hours 27 minutes. What time did he leave one city

The train travels the distance between the two cities 6 hours 27 minutes. What time did he leave one city if he arrived in another at 22 hours 10 minutes?

In order to determine the time of departure of the train from the station of departure, it is necessary to subtract the time during which it was on the way from the time of arrival at the second station, namely 6 hours 27 minutes.
Thus, we get:
22 h 10 min – 6 h 27 min
Since 1 hour = 60 minutes, we decompose 22 hours into hours and minutes. Will be:
21 hours 10 minutes + 60 minutes – 6 hours 27 minutes = 21 hours 70 minutes – 6 hours 27 minutes = 15 hours 43 minutes.
Answer: the train left the station at 15 hours 43 minutes.