Respuesta :

Answer: 3 gallons of water

Step-by-step explanation:

3 gallons of alcohol +3 gallons of water = 6 gallons total

alcohol = 3/6 = 50%
Let x=amount of water added.

let 3+x=amount of alcohol and water in 15% solution.

Let 3 gallons of alcohol=percentage of alcohol*volume of solution

3=0.15*(3 + x)

3=0.45 + 0.15x

2.55=0.15x

2.55/0.15=x or 17 gallons of water added=x