Hi guys

I want to solve this but i don't really know how to calculate proportion of time

I made generator Q matrix

Consider another workshop with two machines that operate independently from one another for Expo(u) distributed times, each. A single repair facility exists with repair times that are Expo()) distributed. i) What is the proportion of time in the long run that the probability that no machine is operating for four different designs: D1) u = 1 = 1; D2) ( = 3, 1 = 1; D3) u = 1; 1 = 3; and D4) u = 1 = 2? ii) Assume now that at most of the two machines can operate at any given time. What is the long-term proportion of time that no machine is working if u = 1 = 1? Q=