The answer to your question is,
Ed is 27. His brother is 9.
How did I get this answer?
Ed's age is twice that of his brother. So of course, when you divide 36 by 2, you would get 18. They are not twins so this wouldn't be the answer. You need to divide 18 by 2 again. This makes 9. If you add 9 to 27, that makes 36. Which is their ages.
-Mabel <3