please help me to answer this..urgent

QUESTION 2 (PO2, CO2, C4, C6) An absorption column is required to scrub an air stream containing 15 mol% of CO2 and reduced its concentration to 5 mol% using water as the scrubbing liquid. The column is designed to operate isothermally at 1 atm pressure. The feed gas flow rate is 330 kgmol/h while the flow of water is 1.5 times the minimum flow. Given the Henry's law constant for CO2 dissolve in water is 3.5 mol fraction gas/mol fraction liquid at the operating temperature. a) Determine the number of theoretical stages required by using graphical method. (12 marks) b) It is desired to reduce the number of theoretical stages in (Q2.a). Proposed significant parameters that can reduce the number of theoretical stages. Justify your answer and state all related assumptions and equations used. (8 marks)