Use/convert the times to the 24 hour clock notation and simply subtract the two to get the answer.
In 24 hour notation
7.30 am = 0730 hours
4.30 pm = 1630 hours
1630-0730=0900 = 9 hours
9 hours and 30 minutes.
7
6
8 hours.
Ten hours.
5 hours and 30 minutes.
10 hours and 45 minutes.
12 hours 30 minutes.
10 hours and 15 minutes.
5.5
9.5
8