Ruby Company produces a chair that requires a standard 5 yards of material per unit. The standard price of one yard of material is $7.60. During the month, 8,500 chairs were manufactured, using 40,000 yards at a cost of $7.50. Determine the (a) direct materials price variance, (b) direct materials quantity variance, and (c) total direct materials cost variance. (d) Is the total direct materials variance favorable or unfavorable? (e) Provide an example of why the results in (d) might occur.