A developer has a plot of land available on which he can build. He can build either office units
  or houses. Let x be the numbers of office units and y the number of houses to be built. 
  He decides to build:
  at least 10 office units and at least 20 houses.
  Planning regulations prevent him from constructing more than 60 buildings in total.    
  Further, each office unit requires 400 squares metres and each house requires 200 square metres of land.
  The total available area of the plot is 16000 square metres.        
  The builder makes a profit of £13,500 on each office unit and a profit of £9,500 on each house.  
  How many houses and how many office units should be built to maximise profits?    
  P = x + y          
  Enter two points for each constraint line to generate a plot in the window below.  
  You should choose points which clearly show the region formed by the constraints.  
  Constraint 1 x y          
  Point 1        
  Constraint 2 x y          
  Point 1        
  Constraint 3 x y          
  Point 1        
  Point 2        
  Constraint 4 x y          
  Point 1        
  Point 2        
[No canvas support]
  Starting with the corner point nearest the origin, (0, 0), enter the corner points in clockwise order:
  Give your answers rounded to 2 decinmal places.          
  Calculate "P" based on your rounded answers.          
    Feasible Region Corner Points x y P    
    Corner Point 1    
    Corner Point 2    
    Corner Point 3    
    Corner Point 4    
  The objective function is maximised at corner point number: