Suppose, the McAdams Performance Garage, Inc., modifies $600000$ cars annually. The director, Ben McAdams, is keen on obtaining a performance measure for assessment and future reference. He requested you to provide a multifactor measure of the previous year$$s performance to serve as a benchmark for future comparison. You have collected the following data: Resource inputs

included labor, $12,000$ hours; $600$ enhancement kits; and energy, $120,000$ kilowatt$-$hours. The average labor cost last year was $75$ dollars per hour, kits cost $$1,200$ each, and energy costs were $$4$ per kilowatt$-$hour.

a$)$ Determine the multifactor productivity?

b$)$ If McAdams employs highly skilled labor, they can modify $700000$ cars annually. By what amount

could labor costs increase without reducing total productivity in part a$?$