well we know that we have 80mL and we also know that those 80mL will represent the "solute" or the 40% of the Tennessee whiskey total which we can say is 100%, so if 80 is the 40%, how much will it be for the 100% in mL?

Answer:

Step-by-step explanation:
Here,
f(x) = y

or , swapping x with y

now to solve for y we get

now we put f inverse x instead of y

I am done.
9/2 or 4.5
hope this helps:)
Please include the diagram