State sales tax $\displaystyle {S}$ is directly proportional to retail price $\displaystyle {p}$. An item that sells for $\displaystyle {164}$ dollars has a sales tax of $\displaystyle {12.32}$ dollars.

Find a mathematical model that gives the amount of sales tax $\displaystyle {S}$ in terms of the retail price $\displaystyle {p}$.

Function: $\displaystyle {S}{\left({p}\right)}=$ Preview Question 6 Part 1 of 2  

What is the sales tax on a $\displaystyle {310}$ dollars purchase. Round to the nearest cent.

The sales tax on a 310 dollar purchase is $ .