Cold Products Corporation manufactured 27.000 ice chests during September. The variable overhead cost allocation base is $13.60 per machine hour. The following variable overhead data pertain to September: Actual Budgeted Production 27.000 units 30.000 units Machine-hours 18.900 hours 18.000 hours Variable overhead cost per machine-hour $13.50 $13.60 What is the variable overhead efficiency variance? 51890 favorable $34,830 unfavorable $36.720 unfavorable 512.240 unfavorable