To find the tax rate we can use the rule of three.
[tex]\begin{gathered} 8\rightarrow100 \\ 8.56\rightarrow x \end{gathered}[/tex]Then,
[tex]x=\frac{8.56\cdot100}{8}=107[/tex]Now, since 8.56 dollars represents 107% of the prices, this means that the tax rate is 7.
