Answer:
True
Explanation:
Opportunity cost refers to the value of a missed chance as a result of deciding a certain way. It is the forfeited benefit of choosing one option over another. Economists determine the opportunity cost by calculating the value of the next best alternative.
If John buys the ticket, it will cost $20. Attending the concert will cause him not to do his homework, as he cannot be in two places at the same time. The consequence of him not doing his homework is the opportunity cost. Attending the concert will, therefore, cost him the $20 and the opportunity cost.