Question 300324
    In a chemistry class, 12 L of a 12% alcohol solution must be mixed with a 20% solution to get a 14% solution. How many liters of the 20% solution are needed?
.
Let x = liters 20% solution to be added
then
.12(12) + .20x = .14(12+x)
.12(12) + .20x = .14(12+x)
1.44 + .20x = 1.68 + .14x
.20x = .24 + .14x
.06x = .24
x = 4 liters