Overhead costs are assigned to clients based on direct labor hours using normal costing. The following information is for the month of September:

Estimated direct labor hours 3,000 hours

Estimated overhead costs $27,000

Actual direct labor hours 2,700 hours

Actual overhead costs $21,600

How is this solved? Apparently the right answer was $2,700 overapplied but I'm not sure how to get this. Thank you in advance!