Number of gears manufactured Plant overhead Plant supervision wages Plant rent Utilities (electricity/water) January February March April 12,000 14,400 10,600 13,800 January April February March $ 45,400 $ 45,400 $ 45,400 $ 45,400 25,900 25,900 25,900 25,900 21,600 23,800 19,500 24,000 Plant repairs & maintenance 16,800 18,400 16,500 18,600 CNC machine tool sharpening 3,600 4,320 3,180 4,140 CNC machine depreciation 18,000 18,000 18,000 18,000 Total plant overhead $131,300 $ 135,820 $128,480 $136,040 Classify each factory overhead costs as fixed, variable or mixed, using number of gears manufactured as the activity driver (also called the cost driver)