The "invisible hand" is
a. used to describe the welfare system in the united states.
b. a concept developed by adam smith to describe the virtues of free markets.
c. a concept used by j. m. keynes to describe the role of government in guiding the allocation of resources in the economy.
d. a term used by some economists to characterize the role of government in an economy — inevitable but invisible.

Gerda, a real estate agent, is selling a moderately priced house in a subdivision. she knows from her uncle that the factory being built half a mile from the subdivision will be manufacturing dog food, using a process that creates a very strong odor that permeates the surrounding neighborhood. a buyer, who is unaware of the type of factory under construction, makes an offer on one of the houses gerda is selling, and within a short time, the deal goes through. what does this scenario best illustrate?

Gary lives in an area that receives high rainfall and thunderstorms throughout the year. which device would be useful to him to maintain his computer?

You are the manager of a large crude-oil refinery. as part of the refining process, a certain heat exchanger (operated at high temperatures and with abrasive material flowing through it) must be replaced every year. the replacement and downtime cost in the first year is $165 comma 000. this cost is expected to increase due to inflation at a rate of 7% per year for six years (i.e. until the eoy 7), at which time this particular heat exchanger will no longer be needed. if the company's cost of capital is 15% per year, how much could you afford to spend for a higher quality heat exchanger so that these annual replacement and downtime costs could be eliminated?