Barry's Tire Service completed 100 tire changes, 6 brake jobs and 16 alignments in 8 hour day with his standard crew of 6 mechanics. A brake specialist costs $16 per hour, a tire charger costs $8 per hour and an alignment mechanics costs $14 per hour. The materials cost for a day was $2000 and overhead cost was $500. Assume the crew .consisted of 2 of each type of mechanic What is the shop's labor productivity if retail price for each service is $60 for tire change, $150 . for brakes and $40 for alignment $7540 .a $2.43 .b $198.4 $12.4 .d