None. A square foot is a 2-dimensional surface. Granules of sand are 3-d objects and therefore cannot fit into a 2-d space.
A square yard of anything is 9 square feet.
The answer will depend on how thinly the sand is spread.
500 sq ft X 1/12 ft / 27 cubic ft./cubic yard = 1.5 cubic yards
5220.5 sq ft
1076.391042 sq. ft.
19681.81 sq ft
32 sq. ft.
1 sq yd are in 9 sq ft
3 sq yards = 3*9 sq ft = 27 sq ft
5468 sq ft
55,000 sq ft.
43055.64 sq. ft.