The Nola Corporation has a standard costing system in which variable snowball manufacturing overhead is assigned to production on the basis of standard machine hours. Their overhead is all related to their factory expenses. Their factory is at full capacity. The following data are available for July: Actual variable snowball manufacturing overhead cdst incurred: $12,350 Variable snowball manufacturing overhead rate variance: $2,110U Actual machine-hours worked: 1,600 hours Total variable snowball manufacturing overhead spending variance: $2,850 U Total variable snowball manufacturing overhead activity variance: $2,250 U The variable overhead efficiency variance for July is: 5740 F $600 $600 F 57400