Answer : The density of an object is 1.2 g/mL
Explanation :
Density : It is defined as the mass contained per unit volume.
Formula used :

Given :
Mass of object = 0.03 kg = 30 g
conversion used : (1 kg = 1000 g)
Volume occupied by object = 25 mL
Now put all the given values in the above formula, we get :

Therefore, the density of an object is 1.2 g/mL