What is the average age of Argentina's athletes who participated in the Summer Olympics in 2012?
AVG(age) where games_name = '2012 Summer' and region_name = 'Argentina';
SELECT AVG(T2.age) FROM games AS T1 INNER JOIN games_competitor AS T2 ON T1.id = T2.games_id INNER JOIN person_region AS T3 ON T2.person_id = T3.person_id INNER JOIN noc_region AS T4 ON T3.region_id = T4.id WHERE T1.games_name = '2012 Summer' AND T4.region_name = 'Argentina'