Units worked per time period

[carmang]

Please help! I'm a newbie and I can't seem to get this simple thing right!!
Using military time.
Example:
A1 - 7/1 23:19
A2 - 7/2 00:15
A3 - =(A2-A1) Custom [h]:mm???
A4 - 98 General??
A5 - ?????
I'm trying to get the average time for the 98 units. I have two separate teams working on the 98 units during the same time period of 58 minutes, but need to show the total 98 even if it is really 49. I have tried several different formulas and no success. Also I would like to exclude the date but not sure how to do that if work goes from one day to the next with military time. How do I get to the .84 time? It seems simple but I can't get it to work out.. working with
Excel 2002