posted by rfvv .
1. He has lunch at 12:00.
2. He has lunch at 12:00 p.m.
3. He has lunch at 12.
4. He has lunch at 12 p.m.
5. He has lunch at noon.
(Are all grammatical?)
6. He goes back home at 15:30 p.m.
7. He goes back home at 15:30.
8. He goes back home at 3:30 p.m.
9. He goes back home at 3:30.
(Are all acceptable?)
Most of us don't use the 24-hour clock, so 6 and 7 would not be acceptable to a lot of Americans.
But It would still be acceptable, just because many don't use does not mean that its not Acceptable. Its still correct.
I've not seen people use PM with the 24 hour clocks. Is that correct? I honestly do not know.