A sample of one liquid has a mass of 60 grams and a volume of 50 centimeters cubed; a sample of a second liquid has a mass of 30 grams and a volume of 40 centimeters cubed. They are put in a container and mixed. Can you determine what the mass and the volume of the mixture is?
mass = 60 g + 30 g = 90 g.
Volume: don't know unless the volumes are additive and I expect they are not.