Q: Mara has 12 bags with 2 marbles in each bag. Markus has 2 bags with 13 marbles in each bag. How many more marbles does Markus have?
A: Mara has 2 x 12 = 24 marbles. Markus has 2 x 13 = 26 marbles. Markus has 26 - 24 = 2 more marbles than Mara. The answer is 2.

Q: Jessica is making an apple pie. She knows that each serving requires 1.5 apples and she has 12 quests. She plans to make 3 pies, which each contain 8 servings. If her guests finish all the pie, on average , how many apples does each guest eat?
A: She is making 24 servings because 3 x 8 = 24. Each guest has 2 servings because 24 / 12 = 2. Each guest has 3 apples because 2 x 1.5 = 3. The answer is 3.

Q: A book library charges fifty cents per day on any book borrowed by its members to read outside the library's premises. At the start of May, Celine borrowed three books from the library to read at home for her upcoming examinations. If she returned one book 20 days after borrowing it, and the other two stayed at her house until the end of May, calculate the total amount of money that she paid at the library for lending the three books.
A:
Celine was charged $0.50 * 20 = $10 for the book she returned to the library after 20 days. If the other two books stayed at her house until the end of May, she paid 31 * $0.50 = $15.5 for each book. For the two books that stayed at her house until the end of May, Celine paid $15.5 * 2 = $31. For the three books, Celine paid $31 + 10 = $41. The answer is 41.