Dave is buying popcorn and sodas for his son and his three friends that he brings to the movies (four kids total). He needs to buy at least one of the two items for each of the four. Popcorn costs $2.50 per bag and sodas cost $4.00 each. Dave can spend at most $20. If s represents the number of sodas he buys and p represents the number of bags of popcorn, then write a system that models this scenario. Can everyone get something to drink?