During a year of operation, a firm collects $350,000 in revenue and spends $80,000 on labor expense, raw materials, rent, and utilities. The firm's owner has provided $600,000 of her own money instead of investing the money and earning a 10% annual rate of return.

a) Calculate the explicit opportunity costs of using market-supplied resources; the implicit opportunity costs of using owner-supplied resources; and total economic cost.

b) Calculate the firm's economic profit and accounting profit.