Ruby Company produces a chair for which the standard specifies 7 yards of material per unit. The standard price of one yard of material is $13.40. During the month, 5,500 chairs were manufactured, using 37,700 yards at a cost of $14.07 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