Write SQL query to solve given problem: Among the customers from a place with more than 20,000 and less than 30,000 inhabitants, how many of them are Machine-op-inspcts?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.GEOID) FROM Customers AS T1 INNER JOIN Demog AS T2 ON T1.GEOID = T2.GEOID WHERE T1.OCCUPATION = 'Machine-op-inspct' AND T2.INHABITANTS_K > 20 AND T2.INHABITANTS_K < 30