1) Benzene (1), toluene (2), styrene (3) and xylene (4) are to be separated in the sequence of distillation columns shown in the figure below. Determine molar flow rates of streams D1, B1, D2 and B2 by using Gauss Elimination method. The compositions of the feed stream and the streams D1, B1, D2 and B2 are shown in the figure (represented by x values). The molar flow rate of the feed stream is 70 mol/min. D x1 = 0.35 x2=0.54 x3 = 0.04 x4=0.07 x1 = 0.20 x1 = 0.16 x2 = 0.40 x3=0.25 x4=0.15 70 mol/min x2 = 0.42 B1 x3 = 0.24 x4 0.18 D2 x1 = 0.21 x2=0.54 x3=0.10 x4=0.15 x1 = 0.01 x2 = 0.10 B2 x3 = 0.65 x4 = 0.24 2) Solve the following linear system by using Gauss Elimination method. Apply partial pivoting in each step of elimination in order to avoid using the relatively small numbers obtained as the basis (pivot) for the calculations. 0.02x1 +0.01x2 = 0.02 x1+2x2+x3 = 1 x2+2x3 + x4 = 4 100x3200x4 = 800