Maximum Outside Arrival Rate For the network$-$of$-$queues with probabilistic routing given in Figure $2\mathrm{.}3,$ sup$-$ posethateachserverservesatanaveragerateof$10$jobs$/$sec;thatis,$\backslash$mu i $=10,$i$.$ Suppose that r$2=$ r$3=1.$ Suppose that p$12=$ p$2,$out $=0\mathrm{.}8,$ p$23=$ p$13=0\mathrm{.}2,$ p$1,$out $=0,$ and p$31=1.$ What is the maximum allowable value of r$1$ to keep this system stable?