How long will a person wait in line on average?

The average time a person spends in the queue is _____enter your response here minutes (round your response to two decimal places).

Twelve customers arrive every hour (Poisson distributed) at Andy Johnson's food truck when it parks outside the Orlando Courthouse from 11-2 p.m. on weekdays. It takes Andy a mean time of 4 minutes to fill each order (following a negative exponential distribution). The Waiting Line Table is provided below and also we know that Wq=Lq