An operator engaged in machining certain components receives an ordinary day rate of $1.60 per day of 8 hours. The standard output for machining the components has been fixed at 80 pieces per hour (time as fixed for premium bonus). On a certain day, the output of the worker on this machine is 800 pieces. Find the labour cost per 100 pieces and th wages that would have been actually earned by the workman under the following: (a) If a bonus of $0.25 is paid per 100 pieces of the extra output (b) If paid for on straight piece work basis at the standard rate (C) If Rowan Plan is adopted (D) If Halsey Premium Bonus system is adopted