The sales tax would be $3.20 and the total cost would be $43.20
Explanation: First you need to find what 8% of 40 would be. In order to do this you need to convert the 8% into a decimal. You do this by multiplying the percent with the whole. In this case, the whole is 40 so if you multiply them you get 3.20 (or 3.2 it's the same thing). That would be the sales tax. To get the total cost you simply add the sales tax with the item.
