Imagine there are two series of science-fictions: The Three-Body Problem (T) and Galactic Empires (G). Your utility function is U = TG, where T is the number of books you consume for The Three-Body Problem, and G is the number of books you consume for Galactic Empires. If your budget is $200, the price of each book of The Three-Body Problem (T) is $50, and the price of each book of Galactic Empires (G) is $100, how many books of The Three-Body Problem (T) will you consume?