Write SQL query to solve given problem: Calculate the average number of cast members that appeared in the credit from the 185th to the 193rd episode.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(COUNT(T1.episode_id) AS REAL) / (193 - 185 + 1) FROM Credit AS T1 INNER JOIN Episode AS T2 ON T1.episode_id = T2.episode_id WHERE T1.category = 'Cast' AND T1.credited = 'true' AND T2.number_in_series BETWEEN 185 AND 193