Answer:
The percent of the cost tax is:
8.5%
Explanation:
Cost of shoe before tax= $ 78
Cost of shoe after tax= $ 84.63
This means that the cost of tax is:
Cost of shoe after tax-cost of shoe before tax
= $ 84.63-$ 78
= $ 6.63
Now, the percent of tax is calculated as:

Hence, the percent tax is:
8.5%