if we take 50 to be the 100%, what's 42 in percentage?
well [tex]\bf \begin{array}{ccllll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
50&100\\
42&x
\end{array}\implies \cfrac{50}{42}=\cfrac{100}{x}[/tex]
solve for "x"
