Alloy A contains copper and zinc in the ratio of 4 : 3 and alloy B contains copper and zinc in the ratio of 5 : 2. A and B are taken in the ratio of 5 : 6 and melted to form a new alloy. The percentage of zinc in the new alloy is closest to:

Solution (By Examveda Team)

\[\begin{array}{*{20}{c}} {{\text{Copper}}}&{}&{{\text{Zinc}}}&{} \\ 4&:&3&{ \Rightarrow {7_{ \times 5}}} \\ 5&:&2&{ \Rightarrow {7_{ \times 6}}} \end{array}\]
\[\begin{array}{*{20}{c}} {{\text{Copper}}\,\,\,\,\,{\text{Zinc}}} \\ {20\,\,\,\,\,:\,\,\,\,\,15} \\ {30\,\,\,\,\,:\,\,\,\,\,12} \\ {\overline {\,50\,\,\,\,\,:\,\,\,\,\,27\,} } \end{array}\]
$${\text{Zinc }}\% = \frac{{27}}{{77}} \times 100 = 35\% $$