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 quantity of pure alcohol to be added be x ounces

70% alcohol is 40 ounces

the total will be x+40 ounces

x+0.7*40 = (x+40)*0.85

x+2.8 =0.85x +34

0.15x=34-2.8

0.15x=31.2

x=208