How much water should be added to 1 gallon of pure antifreeze to obtain a solution that is 60 % antifreeze?

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Answer 1

Pure antifreeze can be taken as 100% antifreeze.  

(1 gal)(100%) = (x gal)(60%)

x = 100/60

x = 1.67 gallons will be the final volume

1.67 gal - 1 gal = 0.67 gallons of water should be added