Question $6(10$ points$)$: A landfill measures $100yd100yd$ at the ground level. The landfill pit $($portion below ground$)$ height and cover $($portion of landfill above$-$ground$)$ height are each $20ft.$ with their side slopes as $1$:$3($vertical: horizontal$).$ Assume a population of $5000$ people, waste generation $=5l\frac{b}{c}a\frac{p}{d},35\%$ waste diversion$/$recycling$,$ and daily cover is $20\%$ of total landfill volume. $($a$)(3$ points$)$ Calculate annual landfill volume utilized by waste and cover material. $($b$)(2$ points$)$ Draw sketch and calculate the volume of landfill pit. $($c$)(2$ points$)$ Draw sketch and calculate the volume of landfill cap. $($d$)(3$ points$)$ Calculate life expectancy of the landfill.