What was the Breeder's Cup Friday attendance for the year the Breeder's Cup Saturday had 52,987?
create table table_24089503_1 (breeders_cup_friday varchar, breeders_cup_saturday varchar, PRIMARY KEY (breeders_cup_friday))
select breeders_cup_friday from table_24089503_1 where breeders_cup_saturday = "52,987"