Answer:
The marginal cost of the 11th plane is $60 million.
Step-by-step explanation:
Marginal cost refers to the cost of producing one more unit of output.
In this case, every unit of output is an airplane. It costs Boeing $500 million to produce 10 airplanes, and $560 million to produce 11 airplanes. SO the marginal cost of the eleventh airplane = cost of producing 11 airplanes - cost of producing 10 airplanes = $560 million - $500 million = $60 million