A grocery store stocks shelves with 120 cartons of strawberries before the store opens. For the first 3 hours the store is open, the store sells 20 cartons per hour. Over the next 2 hours, no cartons of
strawberries are sold. The store then restocks 20 cartons each hour for the next 2 hours. In the final hour
that the store is open, 20 cartons are sold. Graph the function.