An inlet water solution of 100kg/h containing 0.010 wt fraction nicotine (A) in water is stripped with a kerosene stream of 200kg/h containing 0.0005wt fraction nicotine in a countercurrent stage tower. The water and kerosene are essentially immiscible in each other. It is desired to reduce the concentration of the exit water to 0.0010 wt fraction nicotine. Determine the theoretical number of stages needed. The equilibrium data are as follows (C5), with x the weight fraction of nicotine in the water solution and y in the kerosene