Question 1032038
Doing as volume parts, alcohol : water,


{{{(12/17)*s/(s+14)=4/7}}} using s for quantity of the starting mixture.  The proportion here presented is parts per mixture, numerator being the parts as alcohol.


The question asked for "quality" of the alcohol in the mixture.  A more sensible question would be, what QUANTITY of the 12:5 MIXTURE was used to prepare the 4:3 alcohol-to-water mixture.  Solving for s will give that answer.