SELECT COUNT(viewers__m_) FROM table_name_80 WHERE rank__night_ = "n/a" AND timeslot = "8:30 p.m."
Berapa jumlah total pemirsa dengan peringkat (malam) N/A, dan timeslot jam 8:30 malam?
CREATE TABLE table_name_80 (viewers__m_ VARCHAR, rank__night_ VARCHAR, timeslot VARCHAR)