econ 問題~ comparative advantage

assume using the same amount of resources:

china produces 96 bushels of corns and 78 bushel of tea tree.
india produces 80 bushels of corns and 48 bushel of tea tree

a) If we transfer land out of corns into tea tree, how many bushels of corns do we give up in India per additional bushel of tea tree production? In China?

b) Which country has a comparative advantage in corn production? In tea tree production?