SOLUTION: How much 20% antifreeze solution must be mixed with a 80% antifreeze solution to produce 30 gallons of a 60% disinfectant solution?

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Question 636461: How much 20% antifreeze solution must be mixed with a 80% antifreeze solution to produce 30 gallons of a 60% disinfectant solution?
Answer by Maths68(1474) About Me  (Show Source):
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Solution A
===========
Amount = x gallons
Concentration = 20%=0.2



Solution B
===========
Amount = 30-x gallons
Concentration = 80%=0.8

Mixture
=======
Amount = 30 gallons
Concentration = 60% = 0.6


(Amount of Solution A)(Concentration of Solution A)+(Amount of Solution B)(Concentration of Solution B)=(Amount of Mixture)(Concentration of Mixture)
(x)(0.2)+(30-x)(0.8)=(30)(0.6)
0.2x+24-0.8x=18
0.2x-0.8x=18-24
-0.6x=-6
-0.6x/-0.6=-6/-0.6
x=10


10 gallon of 20% antifreeze solution must be mixed with 20 gallons of 80% antifreeze solution to produce 30 gallons of a 60% disinfectant solution.