You may have divided 2 by 20 and multiplied 0.1 by 32. If T is the total before tax, n is the number of items, and p is the price of one item, then $\displaystyle{T}={k}{n}{p}\usepackage{cmbright}\Huge\$ . Substitute the given numbers, $\displaystyle{T}={32}\usepackage{cmbright}\Huge\$ , $\displaystyle{n}={20}\usepackage{cmbright}\Huge\$ , and $\displaystyle{p}={2}\usepackage{cmbright}\Huge\$ , and solve for k.