The standard cost card for one unit of a certain finished product shows the following: Standard Quantity or Hours Standard Price or Rate Direct materials 10 pounds ? per pound Direct labor 3.0 hours $16 per hour Variable manufacturing overhead 4.0 hours $10 per hour The total standard variable cost for one unit of finished product is $90 and the company produces 600 units of finished product in June. Additional information regarding direct materials in June include the following: Actual quantity purchased 5,400 pounds Actual quantity used in production 5,000 pounds What is the materials quantity variance for the month?