Example 2:
Given that: Finishing time, FT = 10:30 p.m.
= 22:30 hours (in 24-hour clock format)
Elapsed time, ET = 1 hour 30 minutes
To find: Starting time
So, STARTING TIME, ST = FT – ET
= 22 hours 30 minutes – 1 hour 30 minutes
= 21:00 hours
= 9:00 p.m. (in 12-hour clock format)