What is the average duration of trips which are started at Adobe on Almaden station to Ryland Park?
trips refer to id; DIVIDE(SUM(duration where start_station_name = 'Adobe on Almaden', end_station_name = 'Ryland Park'), COUNT(id));
SELECT AVG(duration) FROM trip WHERE start_station_name = 'Adobe on Almaden' AND end_station_name = 'Ryland Park'