What is the volume of a rock with a density of 3.00 g/cm3 and a mass of 600g?

The equation of D = m/V

Where D = density
m = mass
and V = volume

We are solving for V, so with the manipulation of variables we multiply V on both sides giving us 
V(D) = m 
now we divide D on both sides giving us
V = m/D 

We know our mass which is 600g and our density is 3.00 g/cm^3
so
V = 600g/3.00g/cm^3 = 200cm^3  or 200mL

a cubic centimeter (cm^3) is one of the units for volume. It's exactly like mL. 1 cm^3 = 1 mL
 
If you wish to change it to L, you'd have to convert. 

One splits the atoms and molecules  the other combines them