When a solid object is completely submerged in ethyl alcohol, its apparent weight is $20\mathrm{.}4$ N and when completely submerged in water, its apparent weight is $11\mathrm{.}0$ N$.$ Determine the volume of the object. Use $790$ kg$/$m$3$ as the density of the ethyl alcohol and $1000$ kg$/$m$3$ as the density of water.