Suppose that there are two countries, A and B, and two goods, X and Y. Country A produces 10 units of X and 20 units of Y per hour, while country B produces 15 units of X and 15 units of Y per hour. The opportunity cost of producing one unit of X in country A is 2 units of Y, and the opportunity cost of producing one unit of X in country B is 1 unit of Y. Find the terms of trade that would be acceptable to both countries.