A prospector finds a solid rock composed of granite (density = 2650 kg/m3) and gold (see table 15.1). The volume of the rock is 3.55 x 10-4 m3, and its mass is 3.81 kg. What mass of gold is contained in the rock? What percentage of the rock is gold, by volume? (Hint: find Vgold/Vrock and express it as a percentage.)