6. A hamburger factory produces 60,000 hamburgers each week. The equipment used costs $10,000 and will remain productive for four years. The labor cost per year is $13,500. a. What is the productivity measure of "units of output per dollar of input" averaged over the four-year period? b. The company has the option of purchasing equipment for $13,000, with an operating life of five years. It would reduce labor costs to $11,000 per year. Should it consider purchasing this equipment (using productivity arguments alone)