Question: What prefixes are priced at pence per minute, fixed at all times with a premium of 3p/min?
Schema: create table table_10408617_5 (prefixes varchar, scheme varchar, approx_premium varchar, PRIMARY KEY (prefixes))
SQL: select prefixes from table_10408617_5 where scheme = "pence per minute, fixed at all times" and approx_premium = "3p/min"