Consider the following linear programming problem:

Minimize 2A + 4B = Z

Constraints:

4A + 6B >= 120 2A + 6B >= 72 B >= 10 A, B >= 0

If after we solved it with solver, we found the optimal solution is A = 15 and B = 10, and the objective value Z = 70. The shadow price for the third constraint (i.e. B >=10) is 2. The allowable increase and the allowable decrease are 10 and 6, respectively. Based on the statements above, which of the following is correct?

1. If you increase the right-hand value of the third constraint to 15, the optimal Z will be equal to 75.

2. none of the above

3. If you increase the right-hand value of the third constraint to 5, the optimal Z will be equal to 65.

4. If you decrease the right-hand value of the third constraint to 9, the optimal Z will stay the same.

5. If you increase the right-hand value of the third constraint to 15, the optimal Z will be equal to 80.