TB MC Qu. 9.72 Dermody Snow Removal's cost formula Dermody Snow Removal's cost formula for its vehicle operating costs $2.990 per month plus $321 per nowdoy. For the month of December the company planned for activity of 6 wlow.days, but the actual level of acuity was 14 snow days. The actual vehicle operating cost for the month was $8.320. The spending variance for vehicle operating cost in December would be closest to