the regular price was "x", which is the 100%.
we also know that Raphael paid 1120 for it and that that is 30% off, namely 100% - 30% = 70%, so 1120 is really the 70% from the original price, so.
[tex]\begin{array}{ccll} amount&\%\\ \cline{1-2} x&100\\ 1120&70 \end{array}\implies \cfrac{x}{1120}=\cfrac{100}{70}\implies \cfrac{x}{1120}=\cfrac{10}{7} \\\\\\ 7x=11200\implies x=\cfrac{11200}{7}\implies x=1600[/tex]
