Barry's Tire Service completed 100 tire changes, six brake jobs, and 16 alignments in an eight-hour ...

Barry's Tire Service completed 100 tire changes, six brake jobs, and 16 alignments in an eight-hour day with his standard crew of six mechanics. A brake specialist costs $16 per hour, a tire changer costs $8 per hour, and an alignment mechanic costs $14 per hour. The materials cost for a day was $2000, and overhead cost was $500.
a.   What is the shop's labor productivity if the retail price for each respective service is $60, $150, and $40?
b.   What is the multifactor productivity, if the crew consisted of two of each type mechanic?