The designer of the penstock for a small hydroelectric cogeneration station has the option of using steel pipe, which costs exist150,000 installed and requires exist5000 yearly for painting and leaking maintenance, or a heavy duty plastic pipe which costs exist 180,000 installed and requires exist 1200 yearly for leak checking maintenance Both options have an expected life of 25 years. If the interest rate is 8%, which option has the lower present worth