dolution

Consider the single-server variation of the nonpreemptive priorities model presented in Sec. 17.8. Suppose there are three priority classes,  The expected service times for priority classes 1, 2, and 3 are 0.4, 0.3, and 0.2,

(a) Calculate W₁, W₂, and W₃.

(b) Repeat part (a) when using the approximation of applying the general model for nonpreemptive priorities presented in Sec. 17.8 instead. Since this general model assumes that the expected service time is the same for all priority classes, use an expected service time  Compare the results with those obtained in part (a) and evaluate how good an approximation is provided by making this assumption.