Assume as in text book the relative price of wheat in terms of cloth for home country in closed economy is 1/2, and for foreign country it is 1. After trade the world price is 2/3. Home coun- try has a comparative advantage in producing wheat so it exports wheat to the foreign country. Under closed economy home country produces 50 units of wheat, after trade it increases its production to due to higher world prices and exports 60 units of wheat