Assume Adia and Zardia can switch between producing wheat and producing beef at a constant rate:
In one hour, Andia can produce 3 Bushels of wheat and 5 pounds of beef.
In one hour Zardia can produce 4 bushels of wheat and 6 pounds of beef.
At which of the following prices would both Andia and Zardia gain from trade with each other? A - 6 bushels of wheat for 10.5 pounds of beef. B - 12 bushels of wheat for 19 pounds of beef. C - 24 bushels of wheat for 34 pounds of beef. (I know the answer is B but do not understand why. Please explain the steps to reach this conclusion).