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_72 (laps INTEGER, time_retired VARCHAR, grid VARCHAR)
### Question:
Which Laps have a Time/Retired of + 4 laps, and a Grid larger than 18?
### Answer:
SELECT AVG(laps) FROM table_name_72 WHERE time_retired = "+ 4 laps" AND grid > 18