The drive up service of a bank will have three tellers and a single waiting line. The average service time for drive-up tellers is 4 minutes per customer and average arrival rate is 36 customers per hour.

What is the average time that a customer, who was not immediately served, would have to wait in line before being served?

Select one:

a.

Approximately 4.3 minutes

b.

Approximately 6.66 minutes

c.

approximately 7.1 minutes

d.

approximately 2.8 minutes