Hien, Inc. uses machine-hours as the base to apply its manufacturing overhead. the following information relates to variable manufacturing overhead standards at Hien:
Standard rate per machine-hour: $50
Total standard machine-hours allowed for units produced during september: 4000
Hien's variable overhead rate variance for september was $800 favorable. Its Variable overhead efficiency variance was $3600 unfavorable. How many machine-hours did Hien actually use during september?