Two traffic signal systems are being considered for an intersection. one system costs $32,000 for installation and has an efficiency rating of 78%, requires 28kw power (output), incurs a user cost of $0.24 per vehicle, and has a life of 10 years. a second system costs $45,000 to install, has an efficiency rating of 90%, requires 34 kw power (output), has a user cost of $0.22 per vehicle, and has a life of 15 years. annual maintenance costs are $75 and $100, respectively. marr = 10% per year. how many vehicles per year must use the intersection to justify the second system when electricity costs $0.08/kwh?