please explain each step for both 3) and 4)

Question 3: A reverse osmosis membrane to be used at 25C for a NaCl feed solution containing 2.5g Naci/L (2.5kg NaCl/ mp=999kg/m) has a water permeability constant Aw = 4.81x10 kg/s.m'atm and a solute (NaCl) permeability constant A, = 4.42x10 m/s. the membrane is concentration polarized such that B=1.5. Calculate the water flux and solute flux through the membrane using AP = 27.2 atm and the solute rejection, R. Also calculate c2 of the product solution Question 4: Use the same feed conditions and pressures given in Question 3. Assume that the cut or fraction recovered of the solvent water will be 0.10. Hence the concentrations of the entering feed solution and the exit feed will not be the same. The flow rate of the permeate water solution is 100gal/h. Calculate Cand c, in kg NaCl/m' and the membrane area in m