Since the discount amount is 20%, here are the steps you must take in order to find the sale price of that certain item that is being sold.
Step 1: Multiply 20 by the discount of 20% in order to find the discount amount and you will get 4.
Step 2: Subtract the original price by the discount amount of 4 in order to find the new sale price of $16.
Hope this helped you and have a good day :)