makes wooden boxes in which to ship motorcycles. Chuck and his three employees invest a total of $20$ hours per day making the $400$ boxes.

a$)$ Their productivity $=20$ boxes$/$hour $($round your response to two decimal places$).$

Chuck and his employees have discussed redesigning the process to improve efficiency. Suppose they can increase the rate to $500$ boxes per day.

b$)$ Their new productivity $=25$ boxes$/$hour $($round your response to two decimal places$).$

c$)$ The unit increase in productivity is boxes$/$hour $($round your response to two decimal places$).$