Now, we need to add the sales tax. To do this we multiply 72 by 1.06. This is because the sales tax is 6% (the decimal form of 6% is 0.06), and we add it on to the 100% cost (which is 1 in decimal form).
(72)(1.06) = 76.32
Therefore the total cost of everything Walter bought plus the tax rate is $76.32.