I need help finding the Present Worth Benefit and Present Worth Cost for Flood control given the table below. ( note there is salvage involved)

Using present worth analysis, determine which alternative is economically more efficient. Interest rate to be used is 12%. Water Supply Flood Control Initial cost ($ million) Annual operation cost ($ million) Annual benefit ($ million) Salvage value ($ million) Lifetime (years) 1 50.0 0.5 15.0 0 10 80.0 0.5 18.0 5.0 5 Question 4 What is PWB for option Flood Control? (Round your answer to six decimal places.) 62.047 x 0% Question 5 What is PWC for option Flood Control? (Round your answer to six decimal places.) 81.802 x 0% Question 6 What is PWNB for option Flood Control? (Round your answer to six decimal places.) 0 ? x 0%