Walden Green provides custom farming services to owners of 5-acre wheat fields. In July, he earned $2,400 by cutting, turning, and balling 3,000 bales. In the same month, the incurred the following costs: gas, $150; tractor maintenance, $115; and labor, $600. His annual tractor depreciation is $1,500. What was Green’s cost per bale? What was his revenue per bale? Should he increase the amount he changes for his services?