how much sand would it take to back fill a 18x10x40" area?

Question

i am building

 a porch and need to know how many tons of sand,

it will take to back fill a 18x10x40" aera.before pooring concrete.

Answer 1

If it's 18' x 10' x 40", that's:

18 x 12 = 216

10 x 12 = 120

40 = 40

216 * 120 * 40 = 1036800 cubic inches or

1036800 / 12^3 = 600 cubic feet

These bags at Home Depot: 

http://www.homedepot.com/p/Unbranded-9-cu-ft-Bulk-Washed-Masonry-Sand-478119/100318372?N=5yc1vZbogdZ1z0u6r2

hold about 9 cubic feet and weigh 1,000 pounds.

600 / 9 = 66.666, so it would be 67 bags totaling 67,000 pounds (aka 33.5 US tons).