Answer:
Jillian sold 15 ten-oz bags and 9 sixteen-oz bags.
Step-by-step explanation:
Let x represent number of 10-oz bags and y represent number of 16-oz bags.
We have been given that Jillian sold 24 boxes of cookies in total. We can represent this information in an equation as:

We are also told that 10 oz. box costs $3.50, while the 16 oz. box costs $5.00, so the cost of x 10-oz bags would be
and cost of y 16-oz bags would be
.
At the end of one week, she collected $97.50. We can represent this information in an equation as:

Now, we will use substitution method to solve our system of equations. From equation (1), we will get:

Substitute this value in equation (2):







Therefore, the number of 10-oz boxes sold be Jillian is 15.
Now, we will substitute
in equation (1) to solve for y.



Therefore, the number of 16-oz boxes sold be Jillian is 9.