125 - 75, so, the difference is 50
how much is 50 in percentage, of 75? well, if we take 75 to be the 100%
then [tex]\bf \begin{array}{ccllll}
amount&\%\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
75&100\\
50&x
\end{array}\implies \cfrac{75}{50}=\cfrac{100}{x}[/tex]
solve for "x"