Mission Corp. uses a standard cost system. Variable overhead is applied using direct labor hours. Standards allowed for each unit are 2.9 hours of fabor at a variable overhead rate of $10. During December, the company manufactured 2,250 units. Variable overhead incurred totaled $73,100. Direct labor payroll totaled $97,750 for 7,120 hours worked a. Calculate the variable overhead rate variance. (Do not round your intermediate calculations. Indicate the effect of variance by selecting "Favorable", "Unfavorable", or "None for no effect i.e., zero variance).) Rate Variance b. Calculate the variable overhead efficiency variance. (Indicate the effect of variance by selecting "Favorable", "Unfavorable", or "None" for no effect (le, tero variance).) Eciency Variance