18- So the equation for density is d=m/v. So if we take the volume of 500ml + 300ml we get a volume of 800ml and a mass of 400g. So we use the equation d=400g/800ml. This gives us a density of 1g/2ml.
19- if we have a ring with a mass of 107g and a volume of 5ml. We will use the following formula d=m/v so this ends up as 21.4=107g/5ml this gives us the material Platinum
