The unit of density [kgm^-3] displays the formula.
So density=mass/volume.
Convert 2160g into kilograms [2160/1000=2.160kg]
Convert volume of 240cm^3 into m^3
100cm=1m
100x100x100=1000000cm^3=1m^3
240/1000000=[2.4x10^-4]
Final calculation
2.160/2.4x10^-4=9000
Answer: 9000kgm^-3