$$

$(15$ pts$)$ A sample having a volume of $100mL$ is titrated with $0\mathrm{.}02N$ NaOH solution as part of an acidity titration. The volume of the titrant used up until the methyl orange endpoint $($ Vmo $)$ is $8ml,$ and the volume of the titrant used up from the methyl orange end point to the phenolphthalein endpoint $(Vp)$ is $17ml.$ Calculate

a$.$ the practically measurable total acidity, and

b$.$ theoretical total acidity in $m\frac{g}{L}$ as $CaC{O}_3.$