If a train's scheduled arrival is at 02:47 hrs, what time must it leave if the run is 1 hour, 57 minutes?

To determine the correct departure time, you need to subtract the duration of the train run from the scheduled arrival time.

The train is scheduled to arrive at 02:47 hrs, and the duration of the run is 1 hour and 57 minutes. Starting with the scheduled arrival time:

• Subtract the hours first:

• 02:47 hrs - 1 hour = 01:47 hrs.

• Now subtract the minutes:

• 01:47 hrs - 57 minutes.

• When you subtract 47 minutes from 01:47 hrs, you get 01:00 hrs.

• You have to subtract an additional 10 minutes to account for the 57 minutes, rolling the time back to 01:00 hrs.

Thus, the train must leave at 01:00 hrs to ensure it arrives at the scheduled time of 02:47 hrs after running for 1 hour and 57 minutes. This is why the correct answer is aligned with the calculated departure time.