How many quarts of water should be mixed with how many quarts of a 30% vinegar solution to obtain 12 qt of a 25% vinegar solution? Hint: Water is 0% vinegar.

Given that total volume of the solution = 12 quarts

Let volume of water added = x quarts

Then volume of 30% vinegar = (12-x) quarts

Given that x quarts of 0% water is mixed with (12-x) quarts of 30% vinegar to obtain 12 quarts of 25% solution

So we can write equation as:

[0% of x] + [30% of (12-x) ] = [25% of 12]

or 0x + 0.30 (12-x) = 0.25*12

or 0 + 3.6-0.30x = 3

or - 0.30x = 3-3.6

or - 0.30x = - 0.6

x=2

Hence answer will be 2 quarts of water.