Molce A stream containing $35\%$ Benzene, $30\%$ Toluene and $35\%$ Xylene; It is desired to separate its components by feeding it to the distillation separation system containing two columns at a molar speed of $2450$ kmol$/$hour$.$ The bottom product of the first column contains $99\%$ Xylene and $1\%$ Toluene by mole, and $98\%$ of the Xylene in the feed stream is desired to be recovered in this stream. The upper product from the first column is fed to the second separation column. It is desired that the upper product obtained from the second column contains $99\%$ mole Benzene and $1\%$ Toluene and $96\%$ of the mole Benzene in the feed stream should be recovered in the upper product of the second column. Considering the figure below, determine the molar velocities of currents D$1,$ D$2,$ B$1$ and B$2$ and the percentage compositions of currents D$1$ and B$2.$