Have 10 cups of solution.10% white vinegar & 90% water. Want 20% vinegar & 80% water. How much vinegar needs added

Question

10 cups of solution. 10% vinegar & 90% water.

Need solution to be 20% vinegar and 80% water.

How much vinegar needs added to get desired amount

 

Answer 1

^x/_{9 cups of water} = ¹/₅ (20% is the same as ¹/₅)

Multiply both sides by 9:

x = ^{1 * 9}/₅

x = ⁹/₅ = 1.8

 

Check:

^1.8/₉ = 0.2

So the total amount of vinegar in the solution will be 1.8 cups.

1.8 - 1 = 0.8 (the total amount minus the original amount is the added amount)

So the amount of vinegar needed to be added is 0.8 cups.