Answer:
Mathematical model:
The sales tax on a 290 dollar purchase is $17.6
Step-by-step explanation:
We're told that sales tax(S) is directly proportional to retail price(p), this can be represented mathematically as;
where k = the proportionality constant
We're also told that when p = $168, S = $10.22, we can solve for k by substituting these values into our equation as see below;
So the mathematical model can be written as;
When p = $290, we can solve for S as shown below;