if we take 80 as the 100%, what is 60 off of it in percentage?
[tex]\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 80&100\\ 60&x \end{array}\implies \cfrac{80}{60}=\cfrac{100}{x}\implies \cfrac{4}{3}=\cfrac{100}{x} \\\\\\ 4x=300\implies x=\cfrac{300}{4}\implies x = 75[/tex]