$3.$ Using a liquid$-$liquid extraction, it is desired to separate ethanol from a two$-$phase mixture of benzene with ethanol at P$\%$ mass and a flow rate of $5000$ Kg$/$h$,$ for this a stream of pure water is used. Determine the amount of water that must be fed so that the ethanol in the water$-$rich phase is Q$\%$ and R$\%$ in the benzene$-$rich phase.a$)$ P $=25\%$ Q $=10\%$R$=5\%$b$)$ P $=30\%$q $=20\%$R $=4\%$c$)$ P $=35\%$Q $=30\%$R $=3\%$d$)$ P $=40\%$Q $=35\%$R $=2\%$e$)$ P $=45\%$Q $=40\%$R $=1\%$