An economy consists of three sectors: coal, steel, and railroads. To produce one unit of coal requires      of a unit of coal,  of a unit of steel, and  of a unit of railroad services. To produce one...

An economy consists of three sectors: coal, steel, and railroads. To produce one unit of coal requires

 of a unit of coal,
 of a unit of steel, and
 of a unit of railroad services. To produce one unit of steel requires
 of a unit of coal,
 of a unit of steel, and
 of a unit of railroad services. To produce one unit of railroad services requires
 of a unit of coal,
 of a unit of steel, and
 of a unit of railroad services. Determine the production levels needed to satisfy an external demand for 300 units of coal, 200 units of steel, and 500 units of railroad services.