Question: How many times is the number of active apps in the event that happened at 7:50:28 on 2016/5/2 than in the event that happened at 7:41:03 on 2016/5/2?
SQL: SELECT SUM(IIF(timestamp = '2016-05-02 7:50:28', 1, 0)) / SUM(IIF(timestamp = '2016-05-02 7:41:03', 1, 0)) AS num FROM events AS T1 INNER JOIN app_events AS T2 ON T1.event_id = T2.event_id WHERE T2.is_active = '1'