Task (To determine the steam consumption in the deflegm

In a continuous distillation column, 1080 kmol/h of a mixture is fed, in which the molar fraction of pentane is 30% and hexane is 70%. In the upper product, the molar fraction of pentane is 95%, in the lower product, the molar fraction of hexane is 90%. Determine the mass costs of the upper and lower products. Determine the flow rate of steam condensing in the deflegmator, if the phlegm number R = 3.0.