Before kerosene can be used as jet fuel, federal regulations require that the pollutants in it be removed by passing the kerosene through clay. Suppose that the clay is in a pipe and that each foot of the pipe will remove 20% of the pollutants that enter it.
If Po is the initial number of pollutant and P(n) represents the quantity of pol- lutants left after n feet pipe, derive an expression for P(n), and we may assume