[The following information applies to the questions displayed below.] Patel and Sons Inc. uses a standard cost system to apply factory overhead costs to units produced. Practical capacity for the plant is defined as 53,700 machine hours per year, which represents 26,850 units of output. Annual budgeted fixed factory overhead costs are $268,500 and the budgeted variable factory overhead cost rate is $3.20 per unit. Factory overhead costs are applied on the basis of standard machine hours allowed for units produced. Budgeted and actual output for the year was 20,700 units, which took 42,700 machine hours. Actual fixed factory overhead costs for the year amounted to $259,300 while the actual variable overhead cost per unit was $3.10. Based on the information provided above, what was (a) the variable overhead spending variance for the year, and (b) the variable overhead efficiency variance for the year? Indicate whether each variance was favorable (F) or unfavorable (U). (Do not round intermediate calculations. Round your final answers to the nearest whole dollar amount.) (a) Spending variance $ 4 (b) Efficiency variance