Suppose the chemist in the application at the beginning of the lesson had to dilute 40 liters of a 12-molar solution by adding 3-molar solution.
a. Write the function that models the concentration of the mixture as a function of the number of liters t of 3-molar solution added.
b. How many liters of 3-molar solution must be added to create a 10-molar solution?