Ruby Company produces a chair for which the standard specifies 5 yards of material per unit. The standard price of one yard of material is $7.50. During the month, 8,500 chairs were manufactured, using 43,600 yards at a cost of $7.55 per yard. Determine the following: Enter favorable variances as negative numbers. a. Direct materials price variance b. Direct materials quantity variance $ c. Total direct materials cost variance $