Billy bob's barber shop knows that a 5 percent increase in the price of their haircuts results in a 15 percent decrease in the number of haircuts purchased. what is the elasticity of demand facing billy bob's barber shop?
a. 0.15
b. 3.0
c. 0.10
d. 0.05

Afirm that makes electronic circuits has been ordering a certain raw material 250 ounces at a time. the firm estimates that carrying cost is i = 30% per year, and that ordering cost is about $20 per order. the current price of the ingredient is $200 per ounce. the assumptions of the basic eoq model are thought to apply. for what value of annual demand is their action optimal?

Starting at age 30, you deposit $2000 a year into an ira account for retirement. treat the yearly deposits into the account as a continuous income stream. if money in the account earns 7%, compounded continuously, how much will be in the account 35 years later, when you retire at age 65? how much of the final amount is interest?

Google started as one of many internet search engines, amazon started as an online book seller, and ebay began as a site where people could sell used personal items in auctions. these firms have grown to be so large and dominant that they are facing antitrust scrutiny from competition regulators in the us and elsewhere. did these online giants grow by fairly beating competition, or did they use unfair advantages? are there any clouds on the horizon for these firms -- could they face diseconomies of scale or diseconomies of scope as they continue to grow? if so, what factors may limit their continued growth?