Darnell and Eleanor are farmers. Each one owns a 10-acre plot of land. The following table shows the amount of barley and alfalfa each farmer can produce per year on a given acre. Each farmer chooses whether to devote all acres to producing barley or alfalfa or to produce barley on some of the land and alfalfa on the rest.

Barley Alfalfa
Darnell 12 6
Eleanor 20 4