Sample Post #$1($Discussion Question $12-4)$If the service rate is not greater than the arrival rate, an infinite queue will eventually build up$.$ Sample Post #$2($Discussion Question $12-7($a$))$Barbershop: usually a single$-$channel, multiple$-$service system $($if there is more than one barber$).$Arrivals $=$ customers wanting haircuts.Waiting line $=$ seated customers who informally recognize who arrived first among them.Service $=$ haircut, style, shampoo, nails, and so forth. If service involves barber, then shampooist, then manicurist, it becomes a multiphase system. Sample Post #$3($Problem $12-12($a$))$Given: l $=10$ cars$/$hour$,$ m $=12$ cars$/$hour$.$The average number of cars in line, Lq $,$ is l$2/$ m $($m l$)=102/12(1210)$