You own a company that makes organs and pianos. Each week you make at least 6 organs and at least 4 pianos. You company can make at most 16 of the instruments in a week. The profit on a piano is $40 and on an organ it is $30. You wish to maximize profit.

Which of the following is NOT a constraint in the situation?

y ≥ 4

P ≤ 30x + 40

x + y ≤ 16

x ≥ 6