A and B are two alloys of gold and copper prepared by mixing metals in the ratio 5 : 3 and 5 : 11 respectively. Equal quantities of these alloys are melted to form a third alloys C. The ratio of gold and copper in the alloy C is -

According to the question,
\[\left. \begin{gathered} {\text{Alloy}}\,{\text{A}} \to 5{ \times _2}:3{ \times _2} = 8{ \times _2} \hfill \\ {\text{Alloy}}\,{\text{B}} \to 5\,\,\,\,\,\,\,\,:11\,\,\,\,\, = 16 \hfill \\ \end{gathered} \right]\]     Equal quantity are mixed

$$\eqalign{ & {\text{Alloy A }} \to 10\,\,\,:\,\,\,6\,\,\,\, = 16 \cr & {\text{Alloy B }} \to {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,5\,\,\,\,\,:\,\,\,11\, = 16 \cr & {\text{Alloy C }} \to {\bf{15}}\,\,\,:\,\,{\bf{17}} \cr} $$