$(15$ points$)$ Consider a carcinogenic volatile organic compound $($VOC$)$ with the dose$-$

response curve shown below. If a $70-kg$ adult breathes $20\frac{m^3}{?}$ day of air containing $3{10}^{-3}$

$m\frac{g}{m^3}$ of this VOC at work $40$ hours per week, $45$ weeks per year, for $30$ years, find the

lifetime cancer risk. $($Hint: you will first need to find the cancer potency slope using the

below graph$)$