The density of rock = 5 g/cm³
Further explanation
Given
Volume of rock=20 cm³
Mass = 100 g
Required 
Density
Solution
Density is a quantity derived from the mass and volume 
Density is the ratio of mass per unit volume 
The unit of density can be expressed in g/cm³ or kg/m³ 
Density formula: 

ρ = density 
m = mass 
v = volume 
Input given values in formula
