Which of the following is an example of a barter system? a. instead of paying for a purchase in mexico in pesos, you use dollars from the united states. b. instead of paying cash for a computer, you use a credit card. c. instead of paying the full amount for a car, you pay 10 percent in cash and the rest in monthly installments. d. instead of paying rent, you clean the house for the owner.

Assume a competitive firm faces a market price of $60, a cost curve of c = 0.003q^3 + 25q + 750, and a marginal cost of curve of: mc = 0.009q^2 + 25.the firm's profit maximizing output level (to the nearest tenth) is , and the profit (to the nearest penny) at this output level is $ will cause the market supply to (shift right/shift left). this will continue until the price is equal to the minimum average cost of $