Last year, Jorge planted corn on all of his 60 acres of property.  Typically, corn grown on good soil yields 400 bushels per acre, but in clay-rich soil, the yield is only half as much per acre as in good soil.  One-third of Jorge's 60 acres of land is clay-rich soil and the rest is good soil.  How many bushels of corn did Jorge's land yield last year?
Jorge has 60 * (1/3) = 20 acres of clay-rich soil.
He has 60 - 20 = 40 acres of good soil.
At 400 bushels per acre, his 40 acres of good soil produced 40 * 400 = 16,000 bushels of corn.
If good soil produces 400 bushels per acre, clay-rich soil produces 400 / 2 = 200 bushels per acre.
At 200 bushels per acre, his 20 acres of clay-rich soil produced 20 * 200 = 4,000 bushels of corn.
Altogether, his land produced 16,000 + 4,000 = 20,000 bushels of corn.