I was working on a question that asked the opportunity costs of going to college per year given that college tuition is $ x $ and the salary per year is $ y $. The answer given is $ x + y $.
I thought that economic costs is given by: $$ \text{Economic costs} = \text{Accounting costs} + \text{Opportunity Costs} $$
Here, the accounting costs would be the explicit cost of tuition, while the opportunity cost would be the implicit cost of wages foregone.
Is my conclusion correct? Or is economic costs synonymous with opportunity costs? (Which makes opportunity cost equal to the total cost, explicit + implicit)?