In two types of stainless steel, ratio of chromium and steel are 2 : 11 and 5 : 21 respectively. In what proportion should two types be mixed so that ratio of chromium to steel in mixed type becomes 7 : 32 ?

According to the question,
\[\begin{gathered} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Chromium}}\,\,{\text{Steel}} \hfill \\ {\text{Type 1}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,2\,\,\,\,:\,\,\,\,\,11 \hfill \\ {\text{Type 2}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,5\,\,\,\,{\text{:}}\,\,\,\,\,\,\,21 \hfill \\ \end{gathered} \]
Now using alligation,

\[{\text{Ratio of quantity }} \to \boxed{\,\,1\,\,\,\,\,\,:\,\,\,\,\,\,2\,\,}\]