How much water must be added to 12 quarts of a 10% solution of salt and water to reduce to a 6% solution?

Let x = quarts of water to be added

so then

12* 10% + x * 0% = (12+x) * 6% (this says 12 quarts of 10% solution + x quarts of 0%(water) equals the new total (12+x) of a 6% solution

1.2 = .72 + .06x

.48 = .06x

x = 8 (quarts of water to be added)

Step-by-step explanation:

Hope this helps

1/4 because there is 4 grades.