. In this slide, queue theory is applied to enhance the service of a bank in lines. For this, firstly a queue model (M/M/C): (GD/∞/∞) is selected to find out efficiency of the servers, number of service facilities, when (days of the week) customers can typically be expected to arrive,amount of time customers has to spend to get the desired service, length of the queue, how much time the customers have to wait before the service starts, how much time the customers have to wait in the bank, human psychology (frustration). After that, the optimal number of counter is calculated to improve the operational efficiency. At last, we calculate the optimal service rate and service efficiency.