Acme Companys production budget for August is 18,900 units and includes the following component unit costs: direct materials, $7.20; direct labor, $11.40; variable overhead, $5.40. Budgeted fixed overhead is $46,000. Actual production in August was 21,840 units. Actual unit component costs incurred during August include direct materials, $9.60; direct labor, $10.80; variable overhead, $6.20. Actual fixed overhead was $48,900. The standard direct labor cost per unit consists of 0.5 hour of labor time at $22.8 per hour. During August, $235,872 of actual labor cost was incurred for 9,360 direct labor hours. Required: Calculate the labor rate variance and labor efficiency variance for August. (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance).)