Table schema:
CREATE TABLE table_22170495_6 (position_in_channel_4s_ratings_a VARCHAR, original_airing_on_channel_4 VARCHAR)

Question: How many position in channel 4s ratings a have February 24, 2010 as the original airing on channel 4?
SQL: SELECT COUNT(position_in_channel_4s_ratings_a) FROM table_22170495_6 WHERE original_airing_on_channel_4 = "February 24, 2010"