What is the maximum length of trench that can be excavated by hand economically rather than by a trenching machine. It will cost $900.00 to transport a trenching machine to the job and back to the storage yard. The trenching machine can excavate 265 linear feet per hour. The trench is 3 ft wide and 4 feet deep. Assume that 4 laborers plus a foreman will be used. Assume a 40-min hour for the hand labor operation and a 45-min hour for the trenching machine. The following cost information applies:
Trenching machine $42.82/hr
Trencher operator $20.45/hr
Laborers,each $16.65/hr
Foreman $28.30/hr