Past exam of the mathematics course of the University of Cambridge / 2010 / ii / Paper 3 / 26I / b / Solution

For a renewal holding time $T$ with mean $m$, the equilibrium residual-life distribution has survivor $m^{-1}{\int }_t^{\infty }\mathbb{P}(T>s)ds$. For C, and also the common long-run B/C renewal structure, $m=2/r$ and the Erlang survivor giveFor A the exponential law is already its own equilibrium delay.