Hello there! So first off, let's find the tax. In order to find the tax of an item, all you have to do is multiply the price by the percentage, because the tax is the portion of the price. The tax is 4%. Let's solve. 20 * 4% (0.04) is 0.8. The tax is $0.80. Let's add that to the purchase price. 20 + 0.80 is 20.80. That's the total purchase price. Here are the answers easier to read.
Sales tax: $0.80
Total price: $20.80