I have a table in Excel that looks something like this:

Date Truck Name Gallons Price
7/31 Truck 1 12.345 2.869
7/31 Truck 2 11.255 2.869
7/31 Truck 3 10.587 2.869
8/3 Truck 1 11.256 2.879
8/3 Truck 2 12.854 2.859
8/4 Truck 1 10.857 2.879
8/4 Truck 3 17.588 2.879

I need to add a 5th column called Previous Fillup.
In this new column I need it to figure out the date of the last fill up for
that particular truck.

Any suggestions?
Thanks in advance...

Scott