It’s Friday night. You already have a ticket to a concert, which cost you $30. A friend invites you to go out for a game of paintball instead. Admission would cost you $25, and you think you’d get $25 worth of enjoyment out of it. Your concert ticket is nonrefundable. What is your opportunity cost(in dollar) of playing paintball?

$30

Explanation:

Opportunity cost is the cost of the next best option forgone when one alternative is chosen over other alternatives.

Here, one has the option of either paintballing or attending a concert. If one goes paintballing , the opportunity to attend the concert is forgone. Thus, the opportunity cost is the cost of the concert tickets- $30.

I hope my answer helps you

they work in some type of way