Write SQL query to solve given problem: Calculate the average of repetitions in the pages that have a total of 100 different words.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(T2.occurrences) AS REAL) / COUNT(T1.page) FROM pages AS T1 INNER JOIN pages_words AS T2 ON T1.pid = T2.pid WHERE T1.words = 100