The analysis of a water sample is shown in the table. The hardness of the water sample is $\_\_\_\_$ $\mathrm{mg} / \mathrm{L}$ as $\mathrm{CaCO}_{3}$.
Atomic weight $(\mathrm{g} / \mathrm{mol}): \mathrm{Ca}=40 ; \mathrm{Mg}=24 ; \mathrm{Na}=23 ; \mathrm{Cl}=35.5 ; \mathrm{S}=32 ; \mathrm{O}=16 ; \mathrm{N}=14$
$$\begin{array}{|c|c|}
\hline
\textbf{Species} & \textbf{Concentration } (\mathrm{mg/L}) \\
\hline
\mathrm{Na}^{+} & 30 \\
\hline
\mathrm{Ca}^{2+} & 10 \\
\hline
\mathrm{Mg}^{2+} & 15 \\
\hline
\mathrm{Cl}^{-} & 30 \\
\hline
\mathrm{SO}_{4}^{2-} & 60 \\
\hline
\mathrm{NO}_{3}^{-} & 5 \\
\hline
\end{array}$$
- $87.5$
- $62.5$
- $25.5$
- $47.5$
