Griffen Company makes pipe using metal. The company uses a standard costing system. Variable overhead is allocated on the basis of direct material usage (pounds). Overhead is allocated to units based on expected production of 13,800 units. Griffen maintains a naterials inventory, so the amount of material used is not necessarily the same as the amount of material purchased in any one month The standard cost sheet for a unit of pipe follows. August financial results show that the average purchase price of metal was $6.30 per pound. The purchase price variance $33,600 unfavorable. The variable overhead efficiency variance was 9,800 unfavorable. Good output produced totaled 16,800 units. Required: a. How many pounds of metal were purchased in August? (Do not round intermediate calculations.) b. What was the direct material efficiency variance in August? (Do not round intermediate calculations. Indicate the effect of each variance by selecting "F" for favorable, or "U" for unfavorable. If there is no effect, do not select either option.) c. How many pounds of metal were used in August? (Do not round intermediate calculations.)