How many businesses in Glendale are reviewed by user with the ID of 20241?
in Glendale refers to city = 'Glendale'
SELECT COUNT(T1.business_id) FROM Business AS T1 INNER JOIN Reviews AS T2 ON T1.business_id = T2.business_id WHERE T1.city = 'Glendale' AND T2.user_id = 20241