A pharmacist has 100 mL of a liquid medication that is 60% concentrated. This means that in 100 mL of the medication, 60 mL is pure medicine and 40 mL is water. She alters the concentration when filling a specific prescription. Suppose she alters the medication by adding water.
a. Write a function that gives the concentration of the medication, d(x), as a function of the amount of water added in milliliters.
b. What is the concentration if the pharmacist adds 20 mL of water?
c. How much water should she add if she needs a 30% concentration?
d. Graph y = d(x). Explain the meaning of the asymptote.