What are the number of games played for students under the age of 20?
select sum ( gamesplayed ) from sportsinfo as t1 join student as t2 on t1.stuid = t2.stuid where t2.age < 20
What are the total hours per week students under the age of 20 played games?
select sum ( hoursperweek ) from sportsinfo as t1 join student as t2 on t1.stuid = t2.stuid where t2.age < 20
What is the most common sport name those students played?
select sportname,count ( * ) from sportsinfo where stuid in ( select stuid from student where age < 20 ) group by sportname order by count ( * ) desc limit 1