The purchase price of a self-propelled combine is US $150,000, and has an expected economic life of 10yr with a salvage value of 10% of the purchase price. At the time of purchase, the prevailing interest rate is 10%, while the general inflation rate is 8%. The combine is used at an average of 10-hr per day and 200 hr per year to harvest maize. The 120 kW engine produces 95 kW of power during combining. Diesel fuel costs $0.30/L, while motor oil costs $1.05/L and labour costs are $6.00 per hour. (a) Calculate the total operating costs per hectare excluding timeliness costs; the timeliness penalty costs, and the total costs per hectare. From the tables, RF1 is 0.08, RF2 is 2.1, Kt is 0.003; pwd is 0.65 at 90% probability level. Determine the optimum capacity for harvesting maize assuming the unit price function is $20,000 per hectare per hour for the combine.