Write SQL query to solve given problem: Of customers who provide other services, how many are from places where inhabitants are more than 20000?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T2.GEOID) FROM Customers AS T1 INNER JOIN Demog AS T2 ON T1.GEOID = T2.GEOID WHERE T1.OCCUPATION = 'Other-service' AND T2.INHABITANTS_K > 20