Final answer:
To create a 6 ounce liquid containing 8% reactor fuel, Mrs. Gargantua needs to use approximately 1.5 ounces of the 4% liquid solution.
Step-by-step explanation:
To solve this problem, we can use the formula for mixing solutions:
(percentage of solution A * quantity of solution A) + (percentage of solution B * quantity of solution B) = (percentage of final solution * quantity of final solution)
Let x be the quantity of the 4% liquid solution Mrs. Gargantua needs to use. Since the final solution is 6 ounces, the quantity of the 20% liquid solution is 6 - x ounces.
Plugging the values into the formula:
(4% * x) + (20% * (6 - x)) = 8% * 6
Solving this equation, we find that x is approximately 1.5 ounces. Therefore, Mrs. Gargantua needs to use 1.5 ounces of the 4% liquid solution.