The Joyce Corporation has a standard costing system in which variable manufacturing overhead is assigned to production on the basis of standard machine-hours. The following data are available for January: Standard machine-hours allowed for January production: Actual variable manufacturing overhead cost incurred: Variable overhead rate variance: Total variable overhead spending variance: Q: Actual machine-hours worked during January is: [A] (Click to select) 500 hours $22,620 $3,420 Unfavorable $4,620 Unfavorable