Alexis bought x boxes of cereal for $3 each, including tax, and paid with a $20 bill. Which expression represents the total amount of change she should receive?

The total cost of x boxes at $3 each is 3x dollars. Subtract that cost from the $20 Alexis paid: 20 − 3x. So the expression is 20 − 3x, choice A.

AI-written and checked against the verified answer.