Two simultaneous reactions are taking place 2A+3B>4D, and B+2D>3U where D is the desired product and U the undesired product. The extent of the first reaction is 10mol/s and that of the second reaction is 5 mol/s. The feed contains 40mols/s of A and 65mol/s of B. The product stream contains 20 moles of A,30 moles of B,30 moles of D, and 15 moles of U. Then selectivity is