Four customers move about among five servers. Upon completion of service at server i, the customer leaves that server and enters service at whichever of the other four servers is free. (Therefore, there are always four busy servers.) The service times at server i are exponential with rate Mi, i = 1,2,3,4,5. If yl1 = 4, M2 = 3, M3 = 8, 44 = 10, and u5 = 7 what proportion of time is each server idle?