The Maxit 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 July: Actual variable manufacturing overhead cost incurred: $23,280 Actual machine-hours worked: 1,900 hours Variable overhead rate variance: $3,870 U Total variable overhead spending variance: $5,280 U Skipped Print The variable overhead efficiency variance for July is