How many ounces of pure acid must be added to 20 ounces of a solution that is 5% acid to strengthen it to a solution that is 24% acid?

1.00x + .05(20)=.24(x + 20)
1.00 represents 100% solution. The variable X represents the unknown amount that will be added. The .05 represents The 5% solution and 20 represents the 20 ounces of the 5% solution. On the right side the .24 represents the 24% solution and the quantity (20+ X) represents the total amount of solution we will have at the end.
Solving the equation:
x + 1 = .24x + 4.8
Subtract .24x from both sides.
.76x + 1 = 4.8
Subtract 1 from both sides.
.76x = 3.8
Divide both sides by .76
x = 5
You must add 5 ounces of 100% pure acid

The answer simplified would be. -6300x