CREATE TABLE table_name_94 (viewers__millions_ VARCHAR(255), airdate VARCHAR(255), channel_4_weekly_rank_a VARCHAR(255))
What is the number of viewers in millions for the episode on October 10, 2008, and a Channel 4 weekly rank a smaller than 30?
    
SQL: SELECT COUNT(viewers__millions_) FROM table_name_94 WHERE airdate = "october 10, 2008" AND channel_4_weekly_rank_a < 30