well, if it was 300 and now is 350, it went up by 50 bucks, that's the inflation amount.
if we take 300 to be the 100%, what is 50 bucks off of it in percentage?
[tex]\begin{array}{ccll} amount&\%\\ \cline{1-2} 300 & 100\\ 50& x \end{array} \implies \cfrac{300}{50}=\cfrac{100}{x}\implies 6=\cfrac{100}{x} \\\\\\ 6x=100\implies x=\cfrac{100}{6}\implies x=\cfrac{50}{3}\implies x\approx 16.7[/tex]
