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_name_29 (rank_by_average INTEGER, competition_finish VARCHAR, average VARCHAR)

### Question ###
Name the sum of rank by average with competition finish more than 8 and average larger than 30

### Accurate SQL ###

SELECT SUM(rank_by_average) FROM table_name_29 WHERE competition_finish > 8 AND average > 30