CREATE TABLE table_name_82 (year INT, tyres VARCHAR, chassis VARCHAR)

How many years were g Tyres and Minardi m187 used?
SELECT AVG(year) FROM table_name_82 WHERE tyres = "g" AND chassis = "minardi m187"
SELECT AVG("year") FROM "table_name_82" WHERE "chassis" = "minardi m187" AND "g" = "tyres"