An average of 18 customers arrive at a service center each hour (Poisson distributed). There are two servers on duty, and each server can process 12 customers per hour (Poisson distributed). Use Table 18-4. a. What is the system utilization? (Round your answer to 2 decimals.) b. What is the average number of customers in the system (waiting plus being served)? (Do not round intermediate calculations. Round your answer to 3 decimals. Ls customers c. What is the average time customers wait in line for service? (Do not round intermediate calculations. Round your answer to 3 decimals.) Wa hours d. What is the average waiting time for customers who actually have to wait? (Round your answer to 3 decimals.) Wa hours