A gold smith has two qualities of gold, one of 12 carats and another of 16 carats purity. In what proportion should he mix both to make an ornament of 15 carats purity ?

Correct Answer: 1 : 3
According to the question,
By using alligation method :
Alligation mcq solution image
Ratio of quantity $$ \to \boxed{\,\,1\,\,\,\,\,\,:\,\,\,\,\,\,3\,\,}$$