QUESTION

A trading company intends to install a small PBX to handle every increasing internal as well as external calls within the company. It is expected that the employees will collectively generate Poisson outgoing external calls with a rate of calls per minute. The duration of these outgoing calls is independent and exponentially distributed with a mean of minutes. Assuming that the PBX has separate external lines to handle the incoming external calls, how many external outgoing lines are required to ensure that the blocking probability is less than 1? You may assume that when an employee receives the busy tone he/she will not make an attempt again.

Public Answer

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