4. Effects of a tariff on international trade The following graph shows the domestic supply of and demand for oranges in Zambia . The world price (PW ) of oranges is $ 780 per ton and is represented by the horizontal black line . Throughout the question . assume that the amount demanded by any one country does not affect the world price of oranges and that there are no transportation or transaction costs associated with international trade in oranges . Also , assume that domestic suppliers will satisfy domestic demand as much as possible before any exporting or importing takes place. 1185 Domestic Demand Domestic Supply 1140 1095 1050 1005 PRICE (Dollars per ton) 980 915 870 825 780 735 0 40 80 120 160 200 240 280 320 360 400 QUANTITY (Tons of oranges) if Zambia is open to international trade in oranges without any restrictions , it will import 320 tons of oranges