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_40 (capacity INTEGER, city VARCHAR, enrollment VARCHAR)
### Question:
What is the average capacity of stadiums in the City of London that belong to schools with an enrollment less than 30,000?
### Answer:
SELECT AVG(capacity) FROM table_name_40 WHERE city = "london" AND enrollment < 30 OFFSET 000