The air in a factory is being filtered so that the quantity of a pollutant, P (in mg/liter), is decreasing according to the function P = P0e-kt, where t is time in hours. If 10% of the pollution is removed in the first five hours:
(a) What percentage of the pollution is left after 10 hours?
(b) How long is it before the pollution is reduced by 50%?
(c) Plot a graph of pollution against time. Show the results of your calculations on the graph.
(d) Explain why the quantity of pollutant might decrease in this way