Question 1156789
---
how much of a 15 % vinegar solution should be added to a 35% vinegar <s>soultion</s> solution to make 12 liters of a 20%  vinegar <s>soultion</s> solution?
----


Add v liters of 15%;


{{{15v+35(12-v)=20*12}}}

-

{{{15v+35*12-35*v=20*12}}}

{{{-35v+15v+35*12=20*12}}}

{{{(15-35)v=20*12-35*12}}}

{{{(35-15)v=12(35-20)}}}

{{{highlight_green(v=12((35-20)/(35-15)))}}}

{{{v=12*(15/20)}}}

{{{v=12(3/4)}}}

{{{highlight(v=9)}}}


----------------------------
----------------------------
9 liters of the 15%
3 liters of the 35%
---------------------------
---------------------------