During the week ended august 28, the following activity took place: 7,400 lb of raw materials were purchased for inventory at a cost of $4.95 per pound. 2,000 cases of finished product were produced. 8,300 lb of raw materials were used. 5,800 direct labor hours were worked at a total cost of $78,300. $35,670 of actual variable overhead costs were incurred. required: calculate each of the following variances. (do not round intermediate calculations. indicate the effect of each variance by selecting "f" for favorable, "u" for unfavorable, and "none" for no effect (i. e., zero