Answer
$\$25,000$
Work Step by Step
To find cost of removing $20\%$ of the pollutants, substitute 20 to x to have:
$f(20)=\dfrac{100,000(20)}{100-20}=\dfrac{2,000,000}{80}=25,000$
Thus, cost of removing $20\%$ of the pollutants from the bayou is $\$25,000$.
