To check that which ordered pair is minimizing the objective function-we will substitute all the ordered pair one by one in the given function and we will calculate the value of C. The ordered pair which will give the minimum value will be the answer.
For (0, 160)
For (55, 70)
For (80, 50)
For (80, 50)
Hence the ordered pair which minimizes the objective function is (80, 50)
The ordered pair which minimizes the function C = 60x + 85y is ordered pair (80, 50). The correct answer between all the choices given is the third choice.