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I understand you're looking for a for Sheldon M. Ross's "Stochastic Processes" (2nd Edition) . This is a classic graduate-level text, and finding complete, accurate solutions is a common challenge.

Mastering Probability: A Guide to the Sheldon M. Ross Stochastic Processes 2nd Edition Solutions

The "Rosetta Stone" of Renewal Theory:

The Elementary Renewal Theorem : $$ \lim_t \to \infty \fracE[N(t)]t = \frac1\mu $$ Where $\mu$ is the mean inter-arrival time.

Chapter 9: Queueing Models