Problem la:

Ruby Company produces a chair that requires a standard $3$ yards of material per unit. The standard price of one yard of material is $$8\mathrm{.}70.$ During the month, $7,400$ chairs were manufactured, using $22,400$ yards at a cost of $$9\mathrm{.}22$ per yard.

Determine the $($a$)$ direct materials price variance, $($b$)$ direct materials quantity variance, and $($c$)$ total direct materials cost variance. Enter favorable variances as negative numbers.