Answer:
Economic profit $10,000
Explanation:
Income earned as an assistant professor = Salary + Interest on bonds = 75000 + 5% on 100,000 = 75000 + 5000
Income earned as an assistant professor = $80,000
Income from the bookstrore = $90,000
In calculating economic profit, opportunity costs are deducted from revenues earned.
Economic profit = $90,000 - $80,000 = $10,000