Question 295596
    How many ounces of pure alcohol must be added to 40 ounces of a 70% alcohol solution to produce an 85% alcohol solution?.
.
Let x = ounces of pure alcohol added
then
x + .70(40) = .85(40+x)
x + 28 = 34 + .85x
.15x + 28 = 34
.15x = 6
x = 6/.15
x = 40 ounces