please Solve part B, thanks

3. Two fresh feed streams containing benzene (B), toluene (T), and xylene (X) are fed to Column 1 in the separation system shown in the diagram below. All of the xylene (X) entering Column 1 is recovered to Stream 3. All of the xylene (X) entering Column 3 is recovered to Stream 6. Of the total benzene (B) in the fresh feed to Column 1, 4% is recovered to Stream 3. All streams are completely labelled. a) Before solving part (b), calculate the number of degrees-of-freedom for each of the following systems. Be sure to give a list (e.g., of unknowns) as well as the number. Number of Number of Number of Degrees-of- System Unknown Independent Additional Freedom Variables Balances Equations Overall Process Column 1 Column 2 Column 3 b) Calculate all unknown flow rates and mass fractions. ma (kg/h) X4B (kg B/kg) (1-X4B) (kg T/kg) m1 (kg/h) 0.80 kg B/kg 0.20 kg T/kg Column 2 1000 kg/h 0.50 kg B/kg 0.30 kg T/kg 0.20 kg X/kg m2 (kg/h) 0.60 kg B/kg 0.40 kg T/kg Column 1 m (kg/h) X5B (kg B/kg) (1-X5p) (kg T/kg) 1000 kg/h 0.30 kg B/kg 0.20 kg T/kg 0.50 kg X/kg Stream 3 mg (kg/h) X3B (kg B/kg) (0.397X3B) (kg T/kg) 0.603 kg X/kg Column 3 Stream 6 ma (kg/h) 0.30 kg T/kg 0.70 kg X/kg