Answer:
 3g/cm³
Step-by-step explanation:
Given parameters: 
Length of the side = 4cm; 
 Volume of the cube = L³ = 4³ = 64cm³ 
Mass of the cube = 192g 
Unknown: 
Density = ? 
Solution: 
The density of a body is its mass per unit volume; 
 Density = 
 
Insert parameters and solve; 
 Density = 
 = 3g/cm³