Answer :
SOLUTION
The fish usually cost $90. A discount of 30% is
[tex]\begin{gathered} \frac{30}{100}\times90 \\ =\frac{30\times90}{100} \\ =\frac{3\times9}{1} \\ =3\times9=27\text{ dollars } \\ \end{gathered}[/tex]So, $27 off the original price of $90 becomes
[tex]\begin{gathered} 90-27 \\ =63 \end{gathered}[/tex]Hence the answer is $63