Calculate the accounting profit or loss as well as the economic profit or loss in each of the following situations:

1. A firm with total revenues of $150 million, explicit cost of $90 million, and implicit costs of $40 million
2. A firm with total revenues of $125 million, explicit cost of $100 million, and implicit costs of $30 million
3. A firm with total revenues of $100 million, explicit cost of $90 million, and implicit costs of $20 million
4. A firm with total revenues of $250,000, explicit cost of $275,000, and implicit costs of $50,000