Problem 22, p. 48

The national economy of Seriland manufactures steel, cars, and machines.

To produce $1 of steel requires $.30 steel, $.15 cars, and $.40 machines.

To produce $1 of cars requires $.45 steel, $.20 cars, and $.45 machines.

To produce $1 of machines requires $.40 steel, $.10 cars, and $.40 machines.

Seriland wants to consume ds dollars of steel, dc dollars of cars, and dm dollars of machinery.

For the coming year let
   s = dollar value of steel produced
   c = dollar value of cars produced
   m = dollar value of machines produced

    s         s          ds 

    c  =  A   c    +     dc

    m         m          dm
 
           
 aij  =   ?       

    A   = ?