I posted this question befo
I need to calculate in a cell the time duration when the user inters start
and end times in the following fashion:

Start End Duration
00:00 00:45 0.75
00:45 01:30 0.75

Start and End times must be in 24hr format. My problem is in the duration. I
am required to calculate the duration like the example above i.e. instead of
showing it as 0:45 min (00:00 (12:00 AM) €“ 00:45 (12:45 AM) = 0:45 minutes,
my client requires it to show as three quarters of an hour in decimal format
(0.75). how can I do that? I need the user to enter 00:00 and 00:45 then the
form will calculate the 0.75.

and got the following solution:
(B2-B1)*24

The Problem:
this works fine with most but not in the following case:
Start End
21:30 1:00
The answer I am getting is -20.5? it should be 3.5
any Idea.
Thanks
Al