Answer:
economic loss of $20,000 per year
Explanation:
The account teller earned an accounting profit = $40,000 per year, but actually has an economic loss.
economic profit / loss = accounting profit - opportunity costs
Opportunity costs are the costs or benefits lost from choosing one activity or investment over another alternative.
The teller's opportunity costs = $50,000 salary + ($100,000 x 10%) savings account = $60,000
economic profit/loss = $40,000 - $60,000 = -$20,000