Table: icf_1971_canoe_sprint
Columns: rank
nation
gold
silver
bronze
total

Question: How many Gold medals for the Nations with 6 or more Bronze medals and 18 or more Silver?
SQL: SELECT AVG("gold") FROM icf_1971_canoe_sprint WHERE "bronze" > 6 AND "silver" > 18

Question: How many Gold medals did the Soviet Union receive?
SQL: SELECT AVG("gold") FROM icf_1971_canoe_sprint WHERE "nation" = 'soviet union'