Answer:
-$20,000
Explanation:
Economic profit takes into account opportunity cost of an activity.
Opportunity cost is the next best option forgone when one alternative is chosen over other alternatives. Opportunity cost is also known as implicit cost.
Because Bobby chose to work at the seafood resutrant, he forgoed the opportunity of working at the county. Thus, his opportunity cost is $30,000.
Also, if he wasn't making use of the restaurant, he could have rented it out. Thus, his opportunity cost of making use of the restaurant is $20,000.
Economic profit = Revenue - (Implicit cost + Explicit cost)
$50,000 - ($20,000 + $30,000 + $20,000) = -$20,000
I hope my answer helps you