abc auto makers has the following fixed annual costs: new factory mortgage $24,500,000 management annual salaries $6,000,000 insurance $1,500,000 equipment $9,000,000 maintenance $300,000 it also has the following unit variable costs: steel $12,000 aluminum $11,000 rubber $5,000 plastics $10,000 leather $5,000 glass $5,000 labor $17,000 given these factors, what is the average per unit cost of producing the fifth car off the assembly line? the 4,000th car? the 7 millionth car?