The recommended time$-$weighted average air concentration for occupational exposure to water$-$soluble hexavalent chromium $($Cr VI$)$ is $0\mathrm{.}5$g$/$m$3.$ This concentration is based on an assumption that the individual is generally healthy and is exposed for $8$ hours per day over a working lifetime $($that is$,$ from age $18$ to $65$ years$).$ Assuming a body weight of $71\mathrm{.}8$ kg and an inhalation rate of $13\mathrm{.}3$ m$3/$d over the working life of the individual, what is the lifetime $(75$ y$)$ CDI?