Question 27219
x amount of pure salt to add


{{{(0.12*25+x)/(25+x)=0.2}}}

-

{{{x+0.12*25=0.2(25+x)}}}

{{{x+0.12*25=0.2*25+0.2x}}}

{{{x-0.2x=0.2*25-0.12*25}}}

{{{x(1-0.2)=25(0.2-0.12)}}}

{{{x=25((0.2-0.12)/(1-0.2))}}}

.

.