We convert 24-hour times and work out elapsed time.
For 24-hour times after noon, subtract 12 for the 12-hour clock: 1830 = 6:30 pm. To find elapsed time, count the hours and minutes from start to finish: 13:15 to 15:45 is 2 hours 30 minutes = 150 minutes.
Remember
- After noon: 24-hour time − 12 = 12-hour pm time.
- Elapsed time = finish − start.