[tex]p\%=\frac{p}{100}\\\\20\%=\frac{20}{100}=\frac{2}{10}=\frac{1}{5}\\\\60min\ of\ \boxed{x}\ is\ 20\%\\\Downarrow\\\frac{60}{x}=\frac{1}{5}\ \ \ \ \ |cross\ multiply\\\\1\cdot x=5\cdot 60\\\\\boxed{x=300}\\\\\underline{Answer:60\ min\ is\ 20\%\ of\ 300\ min.}[/tex]