An irrigation project requires digging and paving an irrigation canal with a length of (30 km) and a semi-circular section with a diameter of (8 m). The work must be completed within one year, and in the event of delay, a fine delay of $200/day. You have two options for work: 1st Option: using standard equipment (excavators, graders and hand labor) had a cost of $10/m³, the job will be finish without delay. 2nd Option: Use a channel trimmer machine with the following specifications: Purchase price ($70,000), it can be sold after its economic life of (5 years) for ($30,000), its speed (10 m/hr), engine diesel with (250 hp) and its work 48 minutes/hr, capacity of crankcase is (50 liters), the number of hours between changing the oil (100 hr), the maintenance cost is (80%) of its depreciation, the price of one liter of fuel ($0.5/liter) and of oil ($1/liter), the operators' wages ($15,000/year), annual operating hours (2000 hr), and the owner must pay taxes of 10% of the average value of the machine. find which of them is more economical?