It depends how thick the pallets are.
16
Depends upon what materials or products are on those pallets. Whether they are cans of Spam or sides of beef will make a huge difference in how many will fit.
20
10 48" x 40" pallets will fit on the floor utilizing the pinwheel method of loading (must utilize 4 way pallets) one goes in straight and the one next to it goes sideways. reverse the loading in the next row and so forth