Write SQL query to solve given problem: Among the repository "3", how many methods whose comments is XML format?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T2.SolutionId) FROM Solution AS T1 INNER JOIN Method AS T2 ON T1.Id = T2.SolutionId WHERE T1.RepoId = 3 AND T2.CommentIsXml = 1