Bulluck Corporation makes a product with the following standard costs: Standard Quantity or Hours Standard Price or Rate Direct materials 5.10 grams $ 2.60 per gram Direct labor 0.60 hours $ 27.00 per hour Variable overhead 0.60 hours $ 3.60 per hour The company reported the following results concerning this product in July. Actual output 4,600 units Raw materials used in production 12,970 grams Actual direct labor-hours 2,500 hours Purchases of raw materials 13,700 grams Actual price of raw materials purchased $ 2.80 per gram Actual direct labor rate $ 13.00 per hour Actual variable overhead rate $ 3.70 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: