A work group of 5 workers in a certain month produced 500 units of output working8 hr/day for 22 days in the month. (a) What productivity measures could be used for this situation, and what are the values of their respective productivity ratios? (b) Suppose that in the next month, the same work group produced 600 units but there were only 20 work-days in the month. Using the same productivity measures as before, determine the productivity index using the prior month as a base.