The model of competitive markets relies on these three core assumptions: 1. There must be many buyers and sellers—a few players can't dominate the market. 2. Firms must produce an identical product—buyers must regard all sellers' products as equivalent. 3. Firms and resources must be fully mobile, allowing free entry into and exit from the industry. The first two conditions imply that all consumers and firms are price takers. While the third is not necessary for price-taking behavior, assume for this problem that a market cannot maintain competition in the long run without free entry. Identify whether or not each of the following scenarios describes a competitive market, along with the correct explanation of why or why not. Scenario Competitive? The government has granted the U. S. Postal Service the exclusive right to deliver mail. There are hundreds of high school students in need of algebra tutoring services in Miami. Dozens of companies offer tutoring services, and the parents who seek out tutors view the quality of the tutoring at the different companies to be largely the same. A few major airlines account for the vast majority of air travel. Consumers view all airlines as providing basically the same service and will shop around for the lowest price. There are hundreds of colleges that serve millions of students each year. The colleges vary by location, size, and educational quality, which enables students with diverse preferences to find schools that match their needs.

The government has granted the U.S. Postal Service the exclusive right to deliver mail. It is not a competitive market. This situation implies that there is a unique seller, which violates the first assumption made (many buyers and sellers), and because of it the U.S Postal Service is not price taking (it can influence on prices).There are hundreds of high school students in need of algebra tutoring services in Miami. Dozens of companies offer tutoring services, and the parents who seek out tutors view the quality of the tutoring at the different companies to be largely the same. It is a competitive market. There are many sellers and many buyers (students' parents) which in practice implies that all of them are price takers. The quality of classes is the same for all companies which implies that the product is homogeneous (identical product), and if tutoring companies can entry or leave the market freely if when convenient (because there is not a law that prohibits entry for example, and if there is more profitable for them they just can go to work to others states of the country), all conditions are fulfilled.A few major airlines account for the vast majority of air travel. Consumers view all airlines as providing basically the same service and will shop around for the lowest price. It is not a competitive market. There are many buyers, but not many sellers, wich implies that companies can collude (agree on higher prices for example). Because of the magnitude of investment related to airline industries, resources are not fully mobile: it is expensive to enter and to exit this market, and that generates a natural barrier to the third principle anounced in the statement. There are hundreds of colleges that serve millions of students each year. The colleges vary by location, size, and educational quality, which enables students with diverse preferences to find schools that match their needs. It is not a competitive market. The product that is commercialized is not identical (education varies by location, size, quality, etc), which means that the service is not homogeneous, therefore, one of the conditions needed is not accomplished.