Question 339805
sterilization tank contains 120 gallons of a solution of 6% bleach 
mixed with pure distilled water. 
needs to be at 4%. 
..
let water required be x  0%
120-x gallons 6%
Mix 120 gallons 4%
...
0+0.06(120-x)=120*0.04
7.20-0.06x=4.80
7.20-4.80 = 0.06x
2.4 = 0.06x
x=40 liters