We need to set up an equation to solve this problem. The sales tax is a percentage of the total, so that's what we are looking for.
Let's call S our sales tax
[tex]420\times S[/tex]
So, that's what we are looking for, and we are given the actual sales tax
[tex]420\times S = 16\\S = 16\div420\\S= .0380[/tex]
So now we have a decimal. In order to convert a decimal into a percentage, we must multiply by 100 (since percentages are out of 100)
[tex].0380\times100=3.8\%[/tex]
The sales tax rate is 3.8%
