Question 945624
Change to concentrations as fraction as milk.


Vessel A:   {{{5/7}}}
Vessel B:   {{{8/13}}}
Expected Mixture Revision: {{{9/13}}}


Taking just a guess, trying to finish having a total number of {{{7*13=91}}} parts.


Taking x parts from vessel A and y parts from vessel be for a total of 91 parts and expected this concentration of {{{9/13}}}.....


{{{((5/7)x+(8/13)y)/91=(9/13)}}}  and {{{x+y=91}}}


When the set of equations makes sense, then you can finish solving for x and y  and their ratio with no real trouble, but just several algebra steps.  You may want to begin by multiplying the rational or complex fractional equation's left side by 1 in the form of  {{{91/91}}}.