A single server queuing system with a Poisson arrival rate and exponential service time has an average arrival rate of 10 customers per hour and an average service rate of 14 customers per hour The average length of time customers wil spend in the system is a 0.1786 minutes Ob. 0.25 minutes Bc 15 minutes Od 10 71 minutes During the early moming hours, customers arrive at a branch post once at an average rate of 39 per hour (Poisson), while clerks can provide services at a rate of 13 per hour. If clerk cost is 541 66 per hour and customer waiting time represents cost of 546 per hour, how many clerks can be justified on a cost bass OaT ODS Oc6 Od 4 Oe5