Answer:
a. The opportunity cost of producing the last hamburger equals the marginal benefit of consumption.
2. a. The market price is determined solely by the forces of supply of and demand for a good.
Step-by-step explanation:
1. Since all the hamburgers are sold at an equilibrium price of $5 and all the hamburgers are sold, that is clear reflection that the opportunity cost that is the benefit foregone in order to produce the last hamburger = the maximum price that the consumer can pay for buying the additional hamburger, that is marginal benefit.
In that case the producer shall always produce the additional hamburger.
Accordingly the outcome in market is economically efficient.
2. When the price is determined by the forces of supply and demand, that is at a point where the intersection of supply and demand forces takes place, it is the most efficient outcome, as at that price maximum consumers are ready to buy, and also maximum supplies are ready to be done, both are satisfied at their levels.