Answer:
Let x = amount of water to be added with 0% antifreeze
1 = amount of pure antifreeze at 100%
x+1 = amount of the mixture at 60% antifreeze
Step-by-step explanation:
1= .60x + .60
Subtract .60 from each side:
1-.60 = .60x
.40 = .60x
Divide both sides by .60
Check: Total antifreeze = 1 gallon in total mixture of 1 + 2/3 gallon = 5/3 gallons. 1 gallon divided by 5/3 equals 3/5 which is 60%. It checks.