A countercurrent system with N equilibrium stages is used to separate acetic acid from water in a ternary system of water$-$acetic acid$-$isopropyl ether Feed is $40$ wt $\%$ acetic acid and $60$ wt $\%$ water. Feed flow rate is

$1000$ kg$/$h$.$ Solvent is a pure isopropyl ether with a flow rate $($S$)$ of $5$ times larger than the minimum required solvent flow rate $($S $=5\backslash$times Smin$).$ The extraction process should decrease theacetic acid concentration in the outlet raffinate stream $($R$1)$ to $5$ wt $\%($xA$,1=0\mathrm{.}05).$Find the minimum solvent flow rate $($Smin$)$

Data for table attached