Kurt brings $10.75 to the movie theater. He spends 60% of the money on a movie ticket. He spends the rest of the money on popcorn. How much money does Kurt spend on popcorn?

"They’re basically in a monopoly selling position," says Russell Winer, chair of the marketing department at NYU’s Stern School of Business. "Since they don’t allow you, theoretically, to bring food into theaters, they can pretty much charge what they feel the market will bear."

Indeed, they do.

In theory, they will charge a price for popcorn where the spread between what it costs them to make another box of popcorn, and what consumers will pay for that box of popcorn is at its highest level.