Hi guys, I am not sure where this question belongs. I have a problem in finding a suitable formula, etc for my problem. My problem is as follows: I have a timetable for trips departing every 5 minutes from point A to B. Each trip takes say 15 minutes and the vehicle then returns back to A for a next trip (also say taking 15 minutes to return). How do I set up a formula to allocate vehicles to the various trips to determine how many vehicles will be required to service such a timetable? Currently I do this by hand (as it is not cost efective to buy any scheduling software) but thought that Excel is so powerful and that there must be a way to do this automatically. I thought that it is almost a FIFO problem but cannot get to a satisfactory answer. Can somebody assist?