Assume: Ghana is more efficient in the production of both cocoa and rice. In Ghana, it takes 10 resources to produce one tone of cocoa, and 13 1/3 resources to produce one ton of rice. So, Ghana could produce 20 tons of cocoa and no rice, 15 tons of rice and no cocoa, or some combination of the two. In South Korea, it takes 40 resources to produce one ton of cocoa and 20 resources to produce one ton of rice
So, South Korea could produce 5 tons of cocoa and no rice, 10 tons of rice and no cocoa, or some combination of the two.