Explain the relationship between households and firms in economics

"in my opinion, we ought to stop making our own drums and accept that outside supplier's offer," said wim niewindt, managing director of antilles refining, n.v., of aruba. "at a price of $21 per drum, we would be paying $4.70 less than it costs us to manufacture the drums in our own plant. since we use 70,000 drums a year, that would be an annual cost savings of $329,000." antilles refining's current cost to manufacture one drum is given below (based on 70,000 drums per year):

Wang distributors has an annual demand for an airport metal detector of 1 comma 350 units. the cost of a typical detector to wang is $400. carrying cost is estimated to be 19% of the unit cost, and the ordering cost is $24 per order. if ping wang, the owner, orders in quantities of 300 or more, he can get a 10% discount on the cost of the detectors. should wang take the quantity discount? \

The recognition of which of the following expenses exemplifies the application of matching expenses with the revenues they produced? multiple choice(a) cost of goods sold. (b) advertising.(c) president's salary.(d) research and development.