Given:
Two sweaters for $17.50 each and a skirt for $19.
The sales tax is 5.5%.
To find the total amount:
The total selling price is,
[tex]\begin{gathered} SP=17.50+17.50+19 \\ =\text{ \$54} \end{gathered}[/tex]If the sales tax is 5.5% then,
[tex]\frac{5.5}{100}\times54=\text{ \$}2.97[/tex]Hence, the total amount is,
[tex]54+2.97=\text{ \$}56.97[/tex]Thus, the correct answer is a. $56.97