because the time shows all the hours in a 24 hour day. To convert from the 12 hour clock to the 24 hour clock is easy - you just need to add 12 to the hours in the day after midday.

Military time, also known as the 24-hour clock, is a system the military uses to eliminate confusion between morning and afternoon hours, since the armed forces are in operation around the clock.

because the time shows all the hours in a 24 hour day. To convert from the 12 hour clock to the 24 hour clock is easy - you just need to add 12 to the hours in the day after midday.