Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_221315_3 (max_mach VARCHAR, max_speed__mph_ VARCHAR)

### Question ###
What was the max mach when the maximum speed was 3887?

### Accurate SQL ###

SELECT max_mach FROM table_221315_3 WHERE max_speed__mph_ = 3887