Customers enter the camera department of a store at the average rate of six per hour. The department is staffed by one employee, who takes an average of 8.0 minutes to serve each arrival. Assume this is a simple Poisson arrival, exponentially distributed service time situation. Use Exhibit 7.12.

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.)

For this problem I took the average number of people (Lq)=A^2/(S*(s-A))=6*6/(7.5-6))=3.20 which is incorrect

Number of people           

d. Another clerk has been hired for the camera department who also takes an average of 8.0 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. Use the closest value of λ/μ in Exhibit 7.12 when determining Lq (i.e., do not interpolate).)

Average total time             minutes