assume i=15.... Solve clearly..

A.8. A new office building is being planned, and you are requested to give an opinion on the al- ternative window systems listed below. Double pane Single pane Initial cost $4.00/f12 $2.00/ft2 Heat loss 10 Bluthr/F/ft2 12 Btufhr/F/ft Assume i = 8 percent; $3.00 per 1,000 Btu cost; " = 40 years; salvage value = 0. Graph the results in terms of $/yr/ft? versus hof"F/ft and determine break-even points, if any. (Ans, break-even = 50.2 hi/ F?)