# Geometric series/Contaminant/Exercise

Appearance

Into a settling pond with a capacity of , at the beginning of each day, water is filled in. It contains of a certain contaminant, and is mixed completely with the water. During each day, by a biological process, the given amount of contaminant is reduced by . At the end of each day, water leaves the pond. Which percentage of the contaminant

will there be in the drain, in the long run, if the pond is filled at the beginning with clear water?