An alcohol solution consists of 5 gallons of pure water and $x$ gallons of alcohol, $x > 0$. Let $f(x)$ be the ratio of the volume of alcohol to the total volume of liquid.
Note that $f(x)$ is the concentration of the alcohol in the solution.

(a) Find a formula for $\ f(x) =$ .

(b) Evaluate $\ f(6)=$ .

(c) What is the zero of $f(x)$? $\ x =$.

(d) What is the horizontal asymptote of $f(x)$? $\ y =$

(e) Enter the letter of the statement which best explains the physical significance of the values you found in (b)-(d).
The horizontal asymptote in (d): .
The zero in (c): .
The value $f(6)$ in (b): .

A  If no alcohol is mixed with the water, then the liquid's alcohol concentration is 0%.
B  This is the alcohol concentration of the liquid if you add 6 gallons of water.
C  How many gallons of alcohol you must add in order to have a liquid with an alcohol concentration of 6%.
D  This is the alcohol concentration of the liquid if you add 6 gallons of alcohol.
E  As you continue to increase the amount of alcohol added, the liquid will eventually have a concentration of nearly 100% alcohol.
F  As you continue to increase the amount of pure water added, the liquid will eventually have an alcohol concentration of nearly 100% water.