Puvo, Incorporated, manufactures a single product in which variable manufacturing overhead is assigned on the basis of standard direct labor-hours. The company uses a standard cost system and has established the following standards for one unit of product: Standard Quantity Standard Price or Rate Standard Cost Direct materials 5.8 pounds $ 0.60 per pound $ 3.48 Direct labor 0.5 hours $ 33.50 per hour $ 16.75 Variable manufacturing overhead 0.5 hours $ 8.50 per hour $ 4.25 During March, the following activity was recorded by the company: The company produced 2,400 units during the month. A total of 19,400 pounds of material were purchased at a cost of $13,580. There was no beginning inventory of materials on hand to start the month; at the end of the month, 3,620 pounds of material remained in the warehouse. During March, 1,090 direct labor-hours were worked at a rate of $30.50 per hour. Variable manufacturing overhead costs during March totaled $14,061. The direct materials purchases variance is computed when the materials are purchased. the variable overhead efficiency variabce for march is