Any formulas/functions for determining LIFO situations?

Hi

I have got an assignment where a number of trucks are coming into a refuelling station, and the cars will be refuelled on a LIFO (last in first out) basis. Each truck takes a different amount of time to refuel (all times are known). I need to work out the exact order of when the trucks leave the refuelling station. As in I need to know for the assignment the exact position that each truck leaves the station at. I know I can do it manually but I was wondering are there any formulas (or a bunch of formulas) that could allow me to determine this automatically. Macros aren't allowed to be used.

Many Thanks

I have attached the sample worksheet where i started doing it manually as an example (the actual worksheet is a lot longer)