Answer
a. Increases
b. Decreases
c. Increases
Work Step by Step
a. As the budget increases, the attainable set of combinations that you can afford increases as you can purchase more books and watch/or more movies.
b. As the price of movie tickets increases, the number of movies you can watch with the given budget decreases and thus the attainable set of combinations you can afford decreases
c. As the price of books fall, the number of books you can afford increase and thus the attainable set of combinations that you can afford increases
