The density is defined as mass of a substance per unit of its volume
It can be expressed in different units like g/L g/m3 Kg/dm3 etc
We are given that
mass of substance = 27.3 grams
volume of substance = 7 cm^3
the density = Mass of substance / volume of substance
density = 27.3g / 7 cm^3 = 3.9 g /cm^3