71/2 hours IF they're both in the same day.
7 hours
8 hours.
2hrs and 30mins
1.5 hours.
7 hours and 30 minutes.
9 + 24k where k is an integer.
7 and a half
At 9:30 AM EST it's 2:30 PM GMT.
4 hours and 15 minutes.
(20.75 - 9.5) hrs = 11.25 hrs = 11 hrs and 15 min
The military normally use the 24 hour clock, so 9:30am would be 0900 hours.