Answer :
[tex]\huge\boxed{6\%}[/tex]
Start by dividing with a calculator.
[tex]58.30\div 55=1.06[/tex]
Subtract [tex]1[/tex], since it represents the cost of a mat.
[tex]1.06-1=0.06[/tex]
Move the decimal two places to the right to convert to a percentage.
[tex]0.06\longrightarrow\large\boxed{6}[/tex]