Please help!

Problem 7-23 (Algo) Customers enter the camera department of a store at an average rate of nine per hour. The department is staffed by one employee, who takes an average of 3.0 minutes to serve each arrival. Assume this is a simple Poisson arrival, exponentially distributed service time situation. (Use the Excel spreadsheet Queue Models.) a-1. As a casual observer, how many people would you expect to see in the camera department (excluding the clerk)? (Round your answer to 2 decimal places.) Number of people a-2. How long would a customer expect to spend in the camera department (total time)? (Do not round intermediate calculations. Round your answer to 1 decimal place.) Average total time minutes b. What is the utilization of the clerk? (Do not round intermediate calculations. Round your answer to 1 decimal place.) Utilization % c. What is the probability that there are more than two people in the camera department (excluding the clerk)?(Do not round intermediate calculations. Round your answer to 1 decimal place.) Probability % d. Another clerk has been hired for the camera department who also takes an average of 3.0 minutes to serve each arrival. How long would a customer expect to spend in the department now? (Do not round intermediate calculations. Round your answer to 1 decimal place.) Average total time minutes