Answer :
$90 -----> 80%
x ---------> 100%
[tex]\begin{gathered} 20\times x=90\times100 \\ 20x=9000 \\ \frac{20x}{20}=\frac{9000}{20} \\ x=450 \end{gathered}[/tex]answer: the original price is $ 450
$90 -----> 80%
x ---------> 100%
[tex]\begin{gathered} 20\times x=90\times100 \\ 20x=9000 \\ \frac{20x}{20}=\frac{9000}{20} \\ x=450 \end{gathered}[/tex]answer: the original price is $ 450