Melbourne Company estimated that machine-hours for the year would be 40,000 hours and overhead (all fixed) would

Question:

Melbourne Company estimated that machine-hours for the year would be 40,000 hours and overhead (all fixed) would be $320,000. Melbourne applies its overhead on the basis of machine-hours. During the year, all overhead costs were exactly as planned ($320,000). There was $44,000 in over applied overhead.
Required
How many machine-hours were worked during the period? Show computations.