Ivanhoe Company applies overhead based on direct labour hours. Two direct labour hours are required for each unit of product. Planned production for the period was set at 8,600 units. Manufacturing overhead is budgeted at $137,600 for the period (20\% of this cost is fixed). The 16,330 hours worked during the period resulted in the production of 8,100 units. The variable manufacturing overhead cost incurred was $110,900 and the fixed manufacturing overhead cost was $28,300. (a) Calculate the variable overhead spending variance for the period