Table 13-6 Wooden Chair Factory Output (chairs Number of Number of produced Marginal Workers Machines per hour) Product Cost of Cost of of Labor Workers Machines Total Cost 0 2 5 10 20 35 55 70 80 19. Refer to Table 13-6. Each worker at the Wooden Chair Factory costs $12 per hour. The cost of each machine is $20 per day regardless of the number of chairs produced. If the factory produces at a rate of 70 chairs per hour and operates 8 hours per day, what is the factory's total labor cost per day? a. $72 C. $576 b. $112 d. $616