What is the 24 hour clock?
It is a system whereby the hours of the day are numbered 1 to 24, rather that 1 to 12 and repeated for AM and PM. 24 hour times are formed by leaving the AM times as they are, and adding 12 hrs to the PM times. For example, 5.30AM remains as 0530 and 5.30PM becomes 1730. The 24-hour day starts at 0001 and ends at 2359.