The Dulac Box plant produces 500 cypress packing boxes in two 10-hour shifts. Due to higher demand, they have decided to operate three 8-hour shifts instead. They are now able to produce 600 boxes per day. What has happened to productivity? It has not changed. It has increased by 37.5 boxes/hr. It has increased by 20%. It has decreased by 8.3%. It has decreased by 9.1%. How would you mathematically figure this problem?