## How to handle “extremes” in M/M/C system in the queue theory?

Hi, I'm beginning to learn queue theory and I have a question. I want try use the queue theory to estimate the indicated server amount to handle operations in a queue. My big problem is that the classical equations for the M/M/C system that I using return "expected" values only to a minimal server range.

For example: If I use $\lambda=15$, $\mu=1$ and $c=10$ in the site http://www.supositorio.com/rcalc/rcalclite.htm, it give me a error, because $c\cdot\mu < \lambda$. But, if I use the site http://www.stat.auckland.ac.nz/~stats255/qsim/qsim.html I can make this evaluation, it give me $W = 19.257$.

My equations implementations give me the same results of the first site, but, I need a implementation that give me results equals from second site. Anybody know if this second site implementation is correct from the queue theory perspective? Where I can find the equations that implements this second approach?

Thanks by help!

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