Problem B During December, a department completed 2,500 units of a product that has a standard materials usage and cost of 1.2 square feet per unit at $0.48 per square foot. The actual material used consisted of 3,050 square feet at an actual cost of $2,664.48. The actual purchase of this material amounted to 4,500 square feet at a total cost of $3,931.20. Compute the materials variances