Break down this math problem: You can buy a movie super ticket for $20 that includes rights to watch any movie and you get one popcorn with a soda for only $1 extra. Or you can buy a movie ticket for $12 and buy one popcorn and a soda at regular price. What's the regular price of popcorn if the soda costs $3 and you didn't buy the super ticket and ended up saving $2?