12 hours
If you are talking about from 12pm-4pm = 4 hours. If you are talking about from 12am-4pm = 16 hours.
0
3 hours between 12pm and 3pm
21
Afternoon: 12pm-6pmMorning: 6am-11:59amEvening: 6pm- 8pmNight:8pm-12amLate Night:12am-5:59am
17 hours
5 hours + 12 hours is 17 hours
12am to 4pm is 16 hours.
12pm to 7pm is a span of 7 hours.
24
Eight hours !