A 100 gal tank contains 10 lb of water. The tank is filled by two inlet streams, one of pure water and one of pure ethanol. The flow rate of both streams is 10 gal/min. Calculate the concentration of ethanol (in weight % and in g/cm³) when the tank is full.

Additional data: The density of ethanol/water solutions is given by the empirical equation

Ρ =  a₀ + a1W + a2W²

where ρ is the specific gravity at 20 ⁰C referenced to water at 4⁰C, W is the weight percent of ethanol in the solution (0-100) and

a₀ = 0.99669, a1 = -0.0012405, a2= -8.3609×10^-6