4.5 hours
From 8:30 AM to 5:00 PM, there are 8 hours and 30 minutes. This can be calculated by counting the hours from 8:30 AM to 5:00 PM, which is 8 hours, plus the additional 30 minutes.
From 8:30 AM to 4:15 PM, there are 7 hours and 45 minutes. This can be calculated by counting the hours from 8:30 AM to 4:00 PM (which is 7 hours) and then adding the additional 15 minutes.
From 8:30 AM to 12:00 AM (midnight) is a total of 15.5 hours. This is calculated by counting the hours from 8:30 AM to 12:00 PM (3.5 hours) and then adding the 12 hours from 12:00 PM to 12:00 AM.
NO
4.5 hours
From 8:30 AM to 5:00 PM, there are 8 hours and 30 minutes. This can be calculated by counting the hours from 8:30 AM to 5:00 PM, which is 8 hours, plus the additional 30 minutes.
From 8:30 AM to 4:15 PM, there are 7 hours and 45 minutes. This can be calculated by counting the hours from 8:30 AM to 4:00 PM (which is 7 hours) and then adding the additional 15 minutes.
From 8:30 AM to 12:00 AM (midnight) is a total of 15.5 hours. This is calculated by counting the hours from 8:30 AM to 12:00 PM (3.5 hours) and then adding the 12 hours from 12:00 PM to 12:00 AM.
NO
If they're both on the same date, then they mark a period of 21/2 hours.
From 8:30 AM to 7:15 PM is a total of 10 hours and 45 minutes. To break it down, from 8:30 AM to 7:00 PM is 10 hours, and then you add the additional 15 minutes. Therefore, the total duration is 10 hours and 45 minutes.
Four pm means 4 o'clock in the afternoon. 10:15 pm means a quarter past ten in the evening. So, there are 6 hours and 15 minutes in between.
From 7:30 AM to 4:00 PM is a total of 8 hours and 30 minutes. To break it down, there are 8 hours from 7:30 AM to 3:30 PM, plus an additional 30 minutes from 3:30 PM to 4:00 PM.
From 7:45 AM to 4:00 PM is a total of 8 hours and 15 minutes. To break it down, there are 8 hours from 7:45 AM to 3:45 PM, plus an additional 15 minutes from 3:45 PM to 4:00 PM. Therefore, the total duration is 8 hours and 15 minutes.
From 5:30 AM to 4:00 PM is a total of 10 hours and 30 minutes. This can be calculated by counting the hours from 5:30 AM to 4:00 PM. Specifically, that's 10 hours from 5:30 AM to 3:30 PM, plus an additional 30 minutes to reach 4:00 PM.
12 hours