SOLUTION: How many liters of a 30% alcohol solution must be mixed with 20 liters of a 70% solution to get a 40% solution?

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Question 572498: How many liters of a 30% alcohol solution must be mixed with 20 liters of a 70% solution to get a 40% solution?
Answer by Maths68(1474) About Me  (Show Source):
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Solution A
Amount = x
Concentration =30% =0.3

Solution B
Amount = 20
Concentration =70% = 0.7

Resultant Solution
Amount =20+x
Concentration =40%=0.4
[Amount Solution A * Concentration A] + [Amount Solution B * Concentration of B] = Amount of Resultant * Concentration of resultant
(x)(0.3)+(20)(0.7)= (20+x)(0.4)
0.3x+14=8+0.4x
0.3x-0.4x=8-14
-0.1x=-6
-0.1x/-0.1=-6/-0.1
x=60


Solution A
Amount = x = 60 liters
Concentration =30% =0.3



60 liters of a 30% alcohol solution must be mixed with 20 liters of a 70% solution to get a 40% solution?