InfoPath Dev

How would I multiply for example, 27:10 hours by 1.5 to get an overtime rate in hours?

Hi. I have a monthly form for our service guys to enter their fuel purchases and mileage in a repeating table. The problem is the mileage.In theory to calculate mileage you subtract the last entry's mileage from the previous months closing mileage (the current month's opening mileage). I have a text box outside the repeating ...