Machine Builders Inc. adopted a standard cost system several years ago that it uses in conjunction with its process cost system. The per-unit standard costs for direct materials and direct labor for its single product are as follows: Materials (4 kilograms x $10.00 per kilogram) $40.00 Labor: (4 hours x $18.00 per hour) 72.00 All materials are issued at the beginning of processing. The company finished producing 8200 units. The budgeted output was 8000 units. The total quantity of material purchased is 30000 kilograms and the company used 28500 kg in the production and stored the rest as inventory What was the direct materials usage variance for July