Presumably by 2400 you mean 24:00 as the time. There is no time 24:00 as a minute after 23:59 would normally be written as 00:00, which would be midnight.
No. After 2300 hours comes 0000. In 24-hour time, the time always means "hours since midnight". 2400 hours would be 0 hours and 0 minutes since midnight, so that time is 0000 hours.
12 AM or 2400
200x12=2400
12 goes into 2400 200 times
Usually, 2400 hours (some say 0000 hours).
2400 m per 12 minutes
200. 12 x 200 = 2400
2400 tiles if you don't get any extra
2400
12:00 a.m. Dec 21
28 800
12:27 ct Saturday, Dec. 6, 2008