To calculate the firm's economic profit, we need to determine the total revenue (TR), total cost (TC), and then find the difference between them. Total Revenue (TR): Total revenue is calculated as price ( P) multiplied by quantity ( Q). = TR=PQ From the previous answers, we have = 70 P=70 and = 3000 Q=3000. = 70 3000 = 210 , 000 TR=703000=210,000 Total Cost (TC): Total cost is calculated as average total cost (ATC) multiplied by quantity ( Q). Given that ATC is constant at $40: = TC=ATCQ = 40 3000 = 120 , 000 TC=403000=120,000 Economic Profit: Economic profit is the difference between total revenue and total cost. Economic Profit = Economic Profit=TRTC Economic Profit = 210 , 000 120 , 000 = 90 , 000 Economic Profit=210,000120,000=90,000 Therefore, the firm's economic profit at the current quantity traded is $90,000