please help with explanation

Schmidt Machinery Company (Exhibit 14.5) used 3,850 pounds of aluminum in June to manufacture 938 units. The company paid $29.20 per pound during the month to purchase aluminum. On June 1, the company had 68 pounds of aluminum on hand. At the end of June, the company had only 48 pounds of aluminum in its warehouse. Schmidt used 4,600 direct labor-hours in June, at an average cost of $42.20 per hour. Required: Compute for June: 1. Schmidt's purchase-price and usage variances for aluminum. Purchase price variance Usage variance 2. Schmidt's direct labor rate and efficiency variances Direct labor rate variance Efficiency variance