Answer:
tax rate is 9%
Step-by-step explanation:
The tax rate can be calculated as:
[tex]r=\frac{p-p_0}{p_0}\cdot 100[/tex]
where
p is the price after tax
p0 is the price before tax
For the sound system in this problem, we have:
[tex]p=8938[/tex] (price after tax)
[tex]p_0=8200[/tex] (proce before tax)
Therefore, the tax rate is:
[tex]r=\frac{8938-8200}{8200}\cdot 100=9\%[/tex]