TOYCO produces toy shovels on a 20-ton press. The steps taken by the press operator to produce one shovel are:

- remove finished shovel and put on conveyor 0.1 min

- remove debris from the dies 0.2 min

- spray dies with oil 0.1 min

- checks raw material (flat sheet) for defects 0.3 min

- places flat sheet into press 0.1 min

- press cycles automatically for 1.0 min

The operator is paid $10/hr and the press costs $100/hr to run.

Raw material in shovel costs $1.00 and it sells for $4.00.

What is the optimum number of presses for one operator for lowest unit cost? Draw the workermachine chart for this situation.