(II) A cube of side length 10.0 $\mathrm{cm}$ and made of unknown
material floats at the surface between water and oil. The oil
has a density of 810 $\mathrm{kg} / \mathrm{m}^{3} .$ If the cube floats so that it is
72$\%$ in the water and 28$\%$ in the oil, what is the mass of the cube and what is the buoyant force on the cube?