
Suppose the production possibilities for two countries, producing either food or clothing, are shown in the above figure. They can each produce any linear combination as well. Measuring food on the horizontal axis, the joint production possibility frontier has a kink because
◦ each country has a marginal rate of transformation that varies with the product mix.
◦ all production possibility frontiers have kinks.
◦ each country has a constant marginal rate of transformation that differs from the other country.
◦ the two countries have the same marginal rate of transformation.