An environmental engineer must recommend one of two methods for monitoring high colony counts of E. coli and other bacteria in watershed area “hot spots.” Estimates are tabulated and the MARR is 10% per year. Use tabulated factors or a spreadsheet for your analysis.

a. Use present worth analysis to select the better method.

b. For a study period of 3 years, use PW analysis to select the better method.

Method A Method B Initial cost, $ 100,000 250,000 Annual operating cost, $ per year 30,000 in year 1, 20,000 increasing by $5000 each year Life, years 3 6