Question

How much water should be added to 3 gallons of pure alcohol in order to obtain a solution that is 50% alcohol?

Answer 1

Answer: 3 gallons of water

Explanation:

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

alcohol = 3/6 = 50%

Answer 2

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