Where the height range is higher than 20000.0 and the shell weight is 12.5, what is the time to feet ratio at 25 degrees?
create table table_16439764_1 (time_to_ft__m__at_25°__seconds_ varchar, shell__lb_ varchar, max_height__ft_ varchar, PRIMARY KEY (time_to_ft__m__at_25°__seconds_))
select time_to_ft__m__at_25°__seconds_ from table_16439764_1 where shell__lb_ = "12.5" and max_height__ft_ > 20000.0