You paid $35 for a ticket (which is non-refundable) to see spam, a local rock band, in concert on saturday. (assume that you would not have been willing to pay any more than $35 for this concert.) your boss called and she is looking for someone to cover a shift on saturday at the same time as the concert. you will have to work 4 hours and she will pay you time and a half, which is $9/hr. what is the opportunity cost of going to the concert?