A train left town A for town B. The journey took 3 hours 40 minutes. The train arrived at town B at 11:05am, what time did the train leave town A?
11:05 - 3:40 = 10:65 - 3:40 = 7:25 AM
11:05 = 11h + 5 min
Train leave town A at:
11h + 5min - ( 3h + 40min ) =
11h - 3 h + 5min - 40 min
5min - 40min = - 35 min
Time cannot be negative, so due to the fact that 1h = 60 min write 11:05 as:
11:05 = 10h + 1h + 5min =
10h + 60min + 5min =
10h + 65min
11h + 5min - ( 3h + 40min ) =
10h + 65min - ( 3h + 40min ) =
10h - 3 h + 65min - 40 min
7h + 25 min
Train leave town A at 7:25 am
To calculate the time the train left town A, we need to subtract the duration of the journey from the arrival time at town B.
First, let's convert the duration of the journey into minutes. Since there are 60 minutes in an hour, 3 hours is equal to 3 * 60 = 180 minutes, and 40 minutes is 40.
So the total duration of the journey in minutes is 180 + 40 = 220 minutes.
Now, let's convert the arrival time at town B into minutes. Since the train arrived at 11:05 am, we can multiply the hours by 60 and add the minutes: 11 * 60 + 5 = 665 minutes.
Finally, subtract the duration of the journey from the arrival time to find the departure time. 665 - 220 = 445.
To convert this back into hours and minutes, divide 445 by 60 to get the hours: 445 / 60 = 7 hours (rounded down).
Therefore, the train left town A at 7:00 am.