A farmer produces both green beans and corn. When the production level of green beans is high relative to the production of corn, the farmer must give up 30 bushels of corn to get 10 more bushels of green beans. If the rate of transformation (or tradeoff) between the two goods is not constant, then when the production level of green beans is low relative to the production of corn, then the opportunity cost of 1 bushel of green beans is:.