Answer
$80\%$.
Work Step by Step
Substitute $f(x)=16$ in the given function.
$\Rightarrow 16=\frac{4x}{100-x}$
Solve the equation for $x$. First multiply both sides by $(100-x)$ to clear fractions.
$\Rightarrow (100-x)16=(100-x)\cdot \left (\frac{4x}{100-x}\right )$
Use distributive property and cancel common factors.
$\Rightarrow 1600-16x=4x$
Add $16x$ to both sides.
$\Rightarrow 1600-16x+16x=4x+16x$
Simplify.
$\Rightarrow 1600=20x$
Divide both sides by $20$.
$\Rightarrow \frac{1600}{20}=\frac{20x}{20}$
Simplify.
$\Rightarrow 80=x$
Hence, $80\%$ of the pollutants can be removed.
