A liquid mixture of benzene$-$toluene is to be distilled in a fractionating column at $101\mathrm{.}32$ kPa pressure. The liquid mixture is fed in the column at $100$kmol$\frac{e}{h}r$ and contains $45$mol$\%$ benzene. A distillate containing $95$mol$\%$ benzene and a bottom containing $10$mol$\%$ benzene was obtained. The reflux ratio is $4$:$1$ and the feed enter the column at its boiling point $).$