What is the alkalinity $($in $m\frac{g}{L}$ as $CaC{O}_3)$ of a water sample with $299m\frac{g}{L}$ of bicarbonate $(HC{O}_3^{-}),20m\frac{g}{L}$ of carbonate $(C{O}_3^{2-}),$ and a $pH$ of $9\mathrm{.}5?$ Note that alkalinity is defined as eq$/L$ of alkalinity $=[HC{O}_3^{-}]+2[C{O}_3^{2-}]+[O{H}^{-}]-[H^{+}]$where $[]=mo\frac{l}{L}$