Lillian went shopping for a new phone because of a sale. The price on the tag was $20, but Lillian paid $16 before tax. Find the percent discount.

First, subtract the sale price from the original price to find the amount of the discount: $20 - $16 = $4

Next, divide the amount of the discount by the original price and multiply by 100 to find the percent discount: ($4 / $20) * 100 = 20%

So, the percent discount is 20%.