if we take 15 as the 100%, then, what the dickens is 120 in percentage of that?
well [tex]\bf \begin{array}{ccllll}
amount&\%\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
15&100\\
120-15&x
\end{array}\cfrac{15}{120-15}=\cfrac{100}{x}[/tex]
solve for "x"
