well, from 72 to 60 we know they're discounted by 12 bucks, since we know 72 is the 100%, how much is 12 off of it in percentage?
[tex]\begin{array}{ccll} amount&\%\\ \cline{1-2} 72&100\\ 12&x \end{array}\implies \cfrac{72}{12}=\cfrac{100}{x}\implies 6=\cfrac{100}{x} \\\\\\ 6x=100\implies x=\cfrac{100}{6}\implies x=16.\overline{66}[/tex]
