“…Sallam and Zobu [22] using simulation data on a queuing model with sequential two stations (stages) and all other conditions well defined, concluded that the simulation results approximated the theoretical results. So many authors have used queuing models in one way or the other among whom are Qureshi et al [21], Srinivas et al [25], Famule [8], Keaogile et al [13] ,Gumus et al [10], Kembe et al [14], Aradhye and Kallurkar [4], Cho et al [6] , Maedeh et al [15], Adan [1], Conte et al [7], Ugwuishiwu et al [27] ,Afrane and Appah [2] , Kama and Mankilik [12], Mukherjee and Whalen [16], Jo et al [11].…”