To create a system of equations for this problem, let's define the variables first:

1. Define Variables:

   • Let $x$ = the number of small boxes purchased.
   • Let $y$ = the number of large boxes purchased.

2. Formulating Equations:

   • Since each small box has 10 granola bars and each large box has 12 granola bars, and we know the camp bought a total of 100 granola bars, we can set up the first equation: $10x + 12y = 100$
   • The camp bought a total of 9 boxes in all, so: $x + y = 9$

3. System of Equations:

   • The system of equations to solve for $x$ and $y$ is: $x + y = 9$ $10x + 12y = 100$

Would you like a step-by-step solution to solve for $x$ and $y$ as well?

Relative Questions to Consider:

1. How would the system of equations change if there were a different total number of granola bars?
2. What if each small box contained 8 granola bars instead of 10?
3. How can substitution help solve this system of equations?
4. What if the camp bought a total of 120 granola bars? How would you modify the equations?
5. Can you solve for the variables if given an additional constraint?

Tip: Always define your variables clearly in word problems to make it easier to translate conditions into equations.