Chapter:Queuing theory

At the present time a servicing department provides answers through one channel, which on average can deal with 24 enquiries/hour at a cost of 3 per enquiry. Increasingly, the customers are complaining that they have to wait for a long time and the department is considering alternative arrangements. These are either a two-service-channel system costing 100/hour and a service rate of 15/hour in each, or a three-service-channel system costing 125/hour and a service rate of 10/hour in each. Customers arrive at the rate of 20/hour. Calculate: (a) the average time a customer spends in the system under the present arrangement. (b) the extra charges per enquiry that would need to be made to recover the extra cost of each of the two arrangements proposed. (c) the implied value of customers time per hour if they agreed to pay the extra costs of the two-channel system.

Please provide well organised and detailed answers .Thank you