Question: what is the country name? | what  did  you  want  to  konw  the country name ?give  more  info about this  question | what are the country names which has both roller coasters with speed higher than 60 and roller coasters with speed lower than 55?
SQL: SELECT T1.name FROM country AS T1 JOIN roller_coaster AS T2 ON T1.Country_ID  =  T2.Country_ID WHERE T2.speed > 60 INTERSECT SELECT T1.name  FROM country AS T1 JOIN roller_coaster AS T2 ON T1.Country_ID  =  T2.Country_ID WHERE T2.speed < 55