Bulluck Corporation makes a product with the following standard costs: Standard Quantity or Hours Standard Price or Rate Direct materials 4.60 grams $ 2.10 per gram Direct labor 0.60 hours $ 22.00 per hour Variable overhead 0.60 hours $ 3.10 per hour The company reported the following results concerning this product in July. Actual output 4,100 units Raw materials used in production 12,470 grams Actual direct labor-hours 2,280 hours Purchases of raw materials 13,200 grams Actual price of raw materials purchased $ 2.30 per gram Actual direct labor rate $ 12.50 per hour Actual variable overhead rate $ 3.20 per hour The company applies variable overhead on the basis of direct labor-hours. The direct materials purchases variance is computed when the materials are purchased. The variable overhead efficiency variance for July is: