if we take 20 to be the 100%, what is 18 in percentage off of it?
[tex]\bf \begin{array}{ccllll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
20&100\\
18&x
\end{array}\implies \cfrac{20}{18}=\cfrac{100}{x}[/tex]
solve for "x".
