density of sand =3.00g/cm3?

Answer 1

The density of sand depends on how wet it is, so does the question says how wet is the sand?

Answer 2

Indeed, density of sand (and other soil related materials) depends on the moisture content.
For dry sand, it is approximately 1.6 g/mL.

Ref:
http://www.rfcafe.com/references/general/density-building-materials.htm

Answer 3

I don't see a question here.