In Problem $6-20,$ you helped Lila Battle determine the optimal order quantity for number $6$ screws. She had estimated that the ordering cost was $$10$ per order. At this time, though, she believes that this estimate was too low. Although she does not know the exact order$-$ ing cost, she believes that it could be as high as $$40$ per order. How would the optimal order quantity change if the ordering cost were $$20,$ $$30,$ and $$40?$