Suppose Brazil and China only trade with each other and they both produce the same two goods: grocery and fish. given its resources, Brazil can prdouce either 2 units of grocery per day or 1 unit of fish; China cna produce either 5 units of grocery or 4 units of fish.
What are the gains from trading a unit of fish if the international price of fish is equal to the average of the local prices in the two countries? (show your work process)