What are the constraints to this problem?

A Virginia Beach farmer has 480 acres of land on which to grow either corn or soybeans.
He figures he has 800 hours of labor available during the crucial summer season. The farmer
can expect a profit of $40 per acre on corn and $30 per acre on soybeans. He knows that
corn requires 2 hours per acre to raise, and soybeans require 1 hour per acre to raise. How
many acres of each should he plant to maximize profit? What is his maximum profit?