A irctid mixture of $50$ male $\%$ af benzene and $40$ mole $\%$ of toluene is charged to a still pot, where a Aayiegirs sistillation is carried out at $1\mathrm{.}2$atm $($absolute$)$ total pressure. How much of the charge must be bohed away to ieave a liquad mixture containing $80$ mole $\%$o toluene. An average relative volatility of $2\mathrm{.}41$ ming be sctepted for the given conditions.