Answer:
The amount of the additional discount is;
[tex]\text{ \$2.04}[/tex]Explanation:
Given that the original price of the shirt is $25.50.
[tex]P=\text{ \$25.50}[/tex]Applying a 20% coupon, we have;
[tex]\begin{gathered} F=P-20\text{\% P} \\ F=P-0.2P \\ F=0.8P \\ F=0.8(\text{ \$25.50)} \\ F=\text{ \$}20.40 \end{gathered}[/tex]The amount after the coupon is $20.40.
so, the value of the additional discount is;
[tex]\begin{gathered} A=\text{ \$20.40 - \$18}.36 \\ A=\text{ \$2.04} \end{gathered}[/tex]Therefore, the amount of the additional discount is;
[tex]\text{ \$2.04}[/tex]