Question

5. He is my … brother, but he is not as smart as I am. a) older b) elder c) the older d) the elder 6. This month I've read two books: The Lord of the Flies and Brave New World. I liked … much more. a) the latter b) the latest c) the later d) the late

Answer 1

5. a) older - просто как прилагательное
6. a) the latter - Пояснение: 

Use latter to refer to the second of two persons or things that have been mentioned. When more than two have been mentioned, use last.
For example:
He preferred oranges to apples, because the latter were not as juicy.
He saw Leathal Weapon 1, 2, and 3 and liked the last one most.