Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_15 (grid INTEGER, time_retired VARCHAR, laps VARCHAR)
### Question:
what is the grid when the time/retired is oil pressure and the laps are more than 50?
### Answer:
SELECT AVG(grid) FROM table_name_15 WHERE time_retired = "oil pressure" AND laps > 50