Sourcebooks Inc., an independent book publisher, buys two items $(30\%$ recycled bright white laser

paper and printer toners$)$ from the same supplier. Sourcebooks pays $$4$ for one pack of paper and

$$12$ for one unit of toner. A setup cost of $$350$ is assumed for all orders. This includes the cost of

tracking and receiving the orders. Holding costs are based on an $8\%$ annual interest rate.

Sourcebooks uses an average of $500$ packs of paper and $80$ units of toner every month.

$($a$)$ Suppose that Sourcebooks orders papers and toners separately. How many packs of papers

and how many units of toners should be ordered? What is the annual cost of holding and

setup?

If both items are ordered and received simultaneously, the setup cost of $$350$ applies to the

combined order.

$($b$)$ Suppose that papers and toners are both ordered when the papers would normally be

ordered. What is the annual cost of holding and setup?

$($c$)$ Suppose that papers and toners are both ordered when the toners would normally be

ordered. What is the annual cost of holding and setup?

$($d$)$ Based on your results from parts $($b$)$ and $($c$),$ should papers and toners be ordered

simultaneously? If so$,$ should they be ordered according to part $($b$)$ or $($c$)?$