Algebra-1

A company produces two products, A and B. Product A requires 3 hours of labor and 2 hours of machine time, while Product B requires 2 hours of labor and 1 hour of machine time. The company has 180 hours of labor and 120 hours of machine time available. The company must produce at least 30 units of Product A. Let a be the number of units of Product A and b be the number of units of Product B (a, b are non-negative integers). Write the system of inequalities that represents this situation. _________.