$-$ S$7\mathrm{.}2$ For the past month, the plant in Problem S$7\mathrm{.}1,$ which has an effective capacity of $6,500,$ has made only $4,500$ hammers per day because of material delay, employee absences$,$ and other problems. What is its efficiency?

$-$ S$7\mathrm{.}3$ If a plant has an effective capacity of $6,500$ and an efficiency of $\backslash (88\backslash \%\backslash ),$ what is the actual $($planned$)$ output?

$-$ S$7\mathrm{.}4$ A plant has an effective capacity of $900$ units per day and produces $800$ units per day with its product mix; what is its efficiency?