Question

A rock occupies a volume of 2cm3 and has a mass of 54 grams. find the density of this rock.

Answer 1

Density is Mass divided by Volume, or; 
$D=\frac{M}{V}\\D=\frac{54g}{2cm^{3}}=27\frac{g}{cm^{3}}$
Your answer is 27 g/cm³.