What is the average price per car produced in Japan?
produced in Japan refers to country = 'Japan'; average price per car = avg(price) where country = 'Japan'
SELECT AVG(T1.price) FROM price AS T1 INNER JOIN production AS T2 ON T1.ID = T2.ID INNER JOIN country AS T3 ON T3.origin = T2.country WHERE T3.country = 'Japan'