To solve this problem, we’ll formulate it as a linear programming (LP) model.

Variables:

• Let $x$ = units of Product A produced
• Let $y$ = units of Product B produced
• Let $z$ = units of Product C produced

Objective Function:

The company wants to maximize its profit. The profit per unit for each product is given, so the objective function becomes: $\text{Maximize } 18x + 12y + 15z$

Constraints:

1. Labor Constraints for each department (based on the hours available per week):

   • Dept. I: $2x + y + 2z \leq 1020$
   • Dept. II: $3x + y + z \leq 1200$
   • Dept. III: $2x + 2y + z \leq 960$

2. Production Requirement: The number of units of Product B produced must be at least the number of units of Products A and C: $y \geq x + z$

3. Non-negativity: $x, y, z \geq 0$

Solution Method:

This is a linear programming problem that can be solved using the Simplex method or an LP solver.

Would you like me to solve this using the values in these equations, or do you want guidance on setting up the solution in an LP solver?

If you'd like to discuss further or have questions on these constraints and objective function, please let me know.

Here are some related questions for exploration:

1. What would the solution be if the profit margins changed?
2. How would an increase in available labor hours affect production?
3. What if the requirement on Product B's units was modified?
4. How sensitive is the solution to changes in Department III's hours?
5. Can the model incorporate a minimum production for each product?

Tip: Understanding the role of constraints helps in modifying the model when requirements or resources change.