The Regional Directorate of Highways puts out a tender for a big gate work planned to be built on the Nide-Ankara highway and determines the benefits and costs of this culvert as follows. If the project analysis period is 50 years, and the interest rate is 6%.

Annual maintenance cost	30000 $ / year
Annual repair cost	50000 $ / year
Annual flood control return	135000 $ / year

a) If a construction company bid $ 2000000 for the cost of the job, what would the benefit-cost ratio be?

b) Highways cannot fully determine whether the $ 2000000 bid is eligible or not, and wants to see how the Benefit-Cost ratio changes between $ 10000000 and $ 30000000 at intervals of $ 200000. Graph and interpret this situation.

c) The construction company entering the tender cannot be sure that the 6% interest rate will remain constant and wants to analyze for different interest rates. If the interest rate changes between 3% and 9% with 1% intervals, how does the Benefit-Cost rate change? (Take the construction cost 2000000 $)

d) Although the project analysis period is determined as 50 years, this number may vary. If the analysis period changes at 5-year intervals between 25 and 75 years, how does the Benefit-Cost ratio change? Graph and interpret it (Take the construction cost 2000000 $ loyalty rate 6%)