You won a free ticket to see a Drake concert. The ticket normally sells for $90, but you cannot sell yours. Arcade Fire is performing on the same night and is your next-best alternative activity. (That is, if you do not go to the Drake concert, you will go to the Arcade Fire concert.) While the price of a ticket to the Arcade Fire is $80, on any given day, you would be willing to pay up to $130 to see Arcade Fire. Assume there are no other costs of seeing either performer.
Based on this information, what is the opportunity cost, in dollars, of seeing Drake?