Hello larrygrace1974.
Each hole is 2'x2'x2' which equals 8 cubic feet.
You have 2 of these so you need 16 cubic feet of concrete.
An 80 lb (36.3 kg) bag of Quikrete yields approximately 0.60 cu ft (17 L).
http://www.quikrete.com/PDFs/DATA_SHEET-Concrete%20Mix%201101.pdf
16 cubic feet / 0.6 cubic feet / per bag = 27 (80#) bags of concrete mix.
Is this what you are looking for?
Chris.
.