Answer: The required quantity of blue food coloring is 9 fluid ounces.
Step-by-step explanation: Given that a mixture contains 4 fluid ounces of water for every 3 fluid ounces of blue food coloring.
We are to find the quantity of blue food coloring that needs to be added to 12 fluid ounces of water.
We will be using the UNITARY method to solve the given problem.
Quantity of blue food coloring that is added to 4 fluid ounces of water = 3 fluid ounces.
So, quantity of blue food coloring that is added to 1 fluid ounce of water is

Therefore, quantity of blue food coloring that is added to 12 fluid ounces of water is given by

Thus, the required quantity of blue food coloring is 9 fluid ounces.