Preston goes to the movies every Sunday afternoon. The movie theater offers 4 combinations of popcorn and beverages: the "mini-combo" costs $5 and includes a small popcorn and a small drink, the "medium-combo" costs $7 and includes a medium popcorn and a medium drink, the "value-combo" also costs $7 and includes a small popcorn and a large drink, and the "large-combo" costs $9 and includes a large popcorn and a large drink. Preston always purchases the "value-combo." We can conclude that: