A waiting$-$line system has $\backslash$lambda $=5,\backslash$mu $=4,$ and M $=2,$ the average time a unit spends in this system will be approximately:

Group of answer choices

$\mathrm{.}2083$

$\mathrm{.}1603$

$\mathrm{.}8013$

$\mathrm{.}4103$