A standard product uses 3 kilograms of direct material costing $4 per kg. During the most recent month, 120 units of the product were manufactured. These required 410 kilograms of material costing $4.50 per kg. It is decided in retrospect that the standard usage quantity of the material should have been 3.5 kg, not 3 kg. What is the materials operational usage variance, if it is chosen to use planning and operational variances for reporting performance? Note. Use minus sign to denote adverse variance. $