There are three alloys $\mathrm { A } , \mathrm { B }$ and C that contain, among other metals, gold and silver in the proportions indicated in the attached table.

\begin{center}
\begin{tabular}{ | c c c | }
\hline
 & Gold (\%) & Silver (\%) \\
\hline
A & 100 & 0 \\
\hline
B & 75 & 15 \\
\hline
C & 60 & 22 \\
\hline
\end{tabular}
\end{center}

It is desired to obtain an ingot of 25 grams, with a proportion of $72 \%$ gold and a proportion of $16 \%$ silver, taking $x$ grams of $\mathrm { A } , y$ grams of B and $z$ grams of C . Determine the quantities $x$, $y , z$.