well, from 273 to 250 is 23 bucks, so that's the difference.
we know 273 is the original price, or namely the 100%, so what's 23 bucks off of it in percentage?
[tex]\begin{array}{ccll} amount&\%\\ \cline{1-2} 273&100\\ 23&x \end{array}\implies \cfrac{273}{23}=\cfrac{100}{x}\implies \implies 273x=2300 \\\\\\ x=\cfrac{2300}{273}\implies x\approx 8.42[/tex]
