QUESTION 1 i) A metallurgical engineer is considering two materials for use in a space vehicle. All estimates are made. Which should be selected on the basis of Annual worth comparison at an interest rate of 15% per year? (10) Material Y Material X First cost, $ Maintenance cost, S per year9,000 Salvage value, $ Life, years -15,000 35,000 2,000 20,000 Solution: ii) Select which alternative using AW and i= (10) 12% - per year. First Cost, $ -200,000 80,000 Annual operating cost, S/year 7,000 -30,000 Salvage value, $ 5,000 Life, years