SELECT DISTINCT T2.name FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name  =  T2.friend WHERE T1.age  <  (SELECT avg(age) FROM person)
Who has friends that are younger than the average age?
SELECT DISTINCT T2.name FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name = T2.friend WHERE T1.age < ( SELECT avg ( age ) FROM person )
select distinct t2 . name from person as t1 join personfriend as t2 on t1 . name = t2 . friend where t1 . age < ( select avg ( age ) from person )
Who has friends that are younger than the average age ?