Question 644151
How many liters of a 70% alcohol must be added to 50 liters of a 40% alcohol solution to produce a 50% alcohol solution ?
.
Let x = amount (liters) of 70% added
then
.70x + .40(50) = .50(x+50)
.70x + 20 = .50x+25
.20x + 20 = 25
.20x = 5
x = 5/.20
x = 25 liters