CREATE TABLE table_name_2 (b_score INT, total VARCHAR, a_score VARCHAR)

Which B Score has a Total larger than 15.325, and an A Score smaller than 6.4?
SELECT SUM(b_score) FROM table_name_2 WHERE total > 15.325 AND a_score < 6.4
SELECT SUM("b_score") FROM "table_name_2" WHERE "a_score" < 6.4 AND "total" > 15.325