Question 949253
You want to use this.


Mixture result, 2 gallons.
Mixture concentration wanted, 50%, or 0.50.
Antifreeze solutions to mix, 70% and 15%, or 0.7 and 0.15.


TRY to use just one variable.
 Let v = how much of the 70% antifreeze to use.
This means, 2-v is how much of the 15% antifreeze to use.


{{{highlight_green(((2-v)15+70v)/2=50)}}}.


Simplify and solve.