# Chapter 27: separate solutions

## Question 1

Compute default review mean.

Effective arrival 2; mean 1/(3-2)=1.

## Question 2

Why is changed stationary mean unavailable?

Arrival 3.6 exceeds service 3, so the M/M/1 queue is unstable.

## Question 3

Does mean 1 prove the transfer receipt arrived after 0.5?

No. It is a planning diagnostic; individual timing needs observed timestamps.