The manager of a grocery store in Decatur currently provides special service to people who still use checks to pay for food. They have a separate pay/bag line for people who insist on waiting for a dollar total to pull out their checkbook and start writing. On average, 30 customers per hour arrive at the checking pay/bag line and they can be modeled with a Poisson distribution. The clerk at this line can handle an average rate of 35 customers per hour and their service can be modeled with exponential distribution.

a. 67%.

b. 75%.

c. 33%.

d. 25%.

Utilization Average time a customer spends in the system

rho = λ/μ w = 1/μ - λ = L/λ

Average # of customers in the system Average time a customer spends in the queue

Ls = λ/μ - λ Wq = λ/μ(μ - λ) = Ls/λ

Average # of customers in queue Probability of n units in the syst