How many machines should be assigned to an operator for lowest cost operations when: a. Loading machine standard time =0.55 minute b. Unloading machine standard time =0.35 minute c. Walk-time between two machines =0.10 minute d. Power-feed time (machine time) =1.60 minute e. Operator rate =18$/hr f. Machine rate =15$/hr Draw an operator machine chart for the optimal solution. Show your calculations