Final answer:
To describe the situation, we can write a system of equations. The cost of a dozen chocolate cookies and a dozen oatmeal cookies can be found by solving the system of equations.
Step-by-step explanation:
To write a system of equations to describe the situation, let's assign variables to the unknown quantities. Let's say the cost of a dozen chocolate cookies is x dollars and the cost of a dozen oatmeal cookies is y dollars.
The first equation represents the sale of 9 dozen chocolate cookies and 8 dozen oatmeal cookies for $110. This can be written as:
9x + 8y = 110
The second equation represents the sale of 9 dozen chocolate cookies and 5 dozen oatmeal cookies for $89. This can be written as:
9x + 5y = 89
We now have a system of two equations with two variables. We can solve this system using any method, such as substitution or elimination, to find the values of x and y.
Once we find the values of x and y, we can determine the cost of a dozen chocolate cookies and a dozen oatmeal cookies, respectively.