A bank has two tellers working on saving accounts. The first teller handles withdraws only. The Second teller handles deposits only. It has been found that service time distributions for both deposits and withdraws are exponential with mean service time $3$ minutes per customer. Depositions are found to arrive in a Poisson fashion throughout the day with mean arrival rate $16$ per hour. Withdrawers also arrive in a Poisson fashion with mean arrival rate $14$ per hour. What would be the effect on the average waiting time for depositors and withdrawers if each teller could handle both withdraws and deposits? What would be the effect if his could only be accomplished by increasing the mean service time to $3\mathrm{.}5$ minutes? $($make the steps simple and write the formulas