if 400,000 is 16%, and "x" is say the 100%
well then [tex]\bf \begin{array}{ccllll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
400,000&16\\
x&100
\end{array}\implies \cfrac{400000}{x}=\cfrac{16}{100}[/tex]
solve for "x".