vitko corporation makes automotive engines for the most recent month budget production was 6,000 engines. the standard power cost is $8.80 per machine hours . the company standards indicates that each engines requires 6.1 maCHINE HOURS . ACTUAL PRODUCTION WAS 6400 ENGINES. ACTUAL MACHINE HOURS WERE 38, 730 ACTUAL POWER COST 350,628 DETERMINE THE RATE AND EFFICIENCY VARIANCE FOR THE VARIABLE OVERHEAD ITEM POWER COST AND INDICATE IF THOSE VARIANCE ARE FAVORABLE OR UNFAVORABLE