Engineering Economy 16th Edition by William Sullivan ,Elin Wicks, Koelling,

Exercise 4

A retrofitted space-heating system is being considered for a small office building. The system can be purchased and installed for $120,000, and it will save an estimated 300,000 kilowatt-hours (kWh) of electric power each year over a six-year period. A kilowatt-hour of electricity costs $0.10, and the company uses a MARR of 15% per year in its economic evaluations of refurbished systems. The market value of the system will be $8,000 at the end of six years, and additional annual operating and maintenance expenses are negligible. Use the benefit-cost method to make a recommendation. (Problem)
Problem
A toll bridge across the Mississippi River is being considered as a replacement for the current 1-40 bridge linking Tennessee to Arkansas. Because this bridge, if approved, will become a part of the U.S. Interstate Highway system, the B-C ratio method must be applied in the evaluation. Investment costs of the structure are estimated to be $17,500,000, and $325,000 per year in operating and maintenance costs arc anticipated. In addition, the bridge must be resurfaced every fifth year of its 30-year projected life at a cost of $1,250,000 per occurrence (no resurfacing cost in year 30). Revenues generated from the toll are anticipated to be $2,500,000 in its first year of operation, with a projected annual rate of increase of 2.25% per year due to the anticipated annual increase in traffic across the bridge. Assuming zero market (salvage) value for the bridge at the end of 30 years and a MARR of 10% per year, should the toll bridge be constructed