System A
Year    Benefit Costs   Nett Saving Discount factor 10% Present value


2011    8500    32,000  -23500  0.909   -21361.50
2012    9500    3100    6400    0.826   5286.40
2013    11500   2500    9000    0.751   6759.00
2014    13500   2700    10800   0.683   7376.40
2015    15500   3000    12500   0.621   7762.50

58500   43,300          5822.80

NPV =   5822.80 - 43300     =   -43,300