CREATE TABLE table_21489362_2 (rr3_pts INTEGER, rr4_pts VARCHAR)
SELECT MIN(rr3_pts) FROM table_21489362_2 WHERE rr4_pts = "20"
เมื่อ 20 คือจุด rr4 จุด rr3 ต่ำสุดคือเท่าใด
When 20 is the rr4 points what is the lowest rr3 points?