please urgent solve all with clear steps

Example A liquid feed (40% n-butane, 25% n-pentane and 20% n-hexane and 15% n-heptane) of 100 mol/h at the boiling point is fed to a distillation tower at 405.3 kPa. It is to be fractionated so that 90% of the n-pentane is recovered in the distillate and 90% of the n- hexane is recovered in the bottom. Find: The minimum number of stages The minimum reflux ratio The number of stages at R=1.5Rmin and feed stage location 1. 2. 3. The following expression can be used for the K-value: In K Qy1 +972 + axo + ap In(P) + 4p2 + apg Tin R; P in psi T P T P2