Liquid-liquid extraction worked example

Worked example to the following problem: If 1000 kg/h of a nicotine (C)-water (A) solution containing 1 wt% nicotine is to be counter currently extracted with kerosene at 20°C to reduce the nicotine content to 0.1 wt%, determine (a) the minimum kerosene rate, and (b) the number of theoretical stages required if 1150 kg of kerosene is used per hour. Adapted from Illustration 10.4, Mass Transfer Operations, 3rd ed, Robert E. Treybal