please explain how did they got the interest rate $3.18/hr and $0.72/hr?

Equipment Cost Data Equipment Purchase Price 1. Line-haul tractors =$120,000 2. Trailers =$40,000 ( 53 -foot dry van) Depreciation 1. Tractors =5-year straight line 2. Trailers =8-year straight line Interest 1. Tractors =6 percent APR for 5 years 2. Trailers =6 percent APR for 8 years Fuel 1. $3.83 per gallon for diesel 2. Line-haul tractors =6.0 miles per gallon Labor Cost 1. Line-haul drivers =$0.45 per mile 2. PUD operation drivers =$22.00 per hour Miscellaneous 1. Insurance cost =$0,067 per mile 2. Maintenance cost =$0.152 per mile 3. Billing cost =$1.95 per freight bill 4. Tractors and trailers are available for use 365 days, 24 hours per day 5. Administrative overhead cost =10 percent of total cost of move Route and Time of Move The shipment originates on June 2, 2017, from The Pennsylvania State University (located 35 miles from the carrier's dispatch/maintenance facility). A linehaul tractor and trailer are dispatched from the terminal at 7:30 a.m. (all times are Eastern Standard Time) and arrive at the shipper's dock at 8:30 a.m. The shipment is loaded from 8:30 a.m. to 12:00 p.m. Driver and tractor remain at Penn State during loading to visit the famous Nittany Lion statue. Driver and vehicle return to the carrier's terminal at 1:00 p.m. to pick up paperwork. Total time for pickup =5.5 hours Total distance for pickup =70 miles The vehicle and the driver depart from the terminal at 1:00pm. on the same day for Dallas, Texas. The driver operates from 1:00 p.m. to 11:00 p.m. and travels 450 miles. The driver rests from 11:00 p.m. to 7:00 a.m. (on June 3) in Knoxville, Tennessee, and then operates another 8 hours (7:00 a.m. to 3:00p.m.) and 375 miles, The driver rests again from 3:00 p.m. to 11:00 p.m. in Memphis, Tennessee. The driver concludes the trip by traveling 450 miles from 11:00 p.m. to 9:00a.m. (June 4) to the consignee in Dallas, the Dallas Cowboys' training facility. Total time for line-haul =44 hours or 1.83 days Total distance for line-haul =1,275 miles The trailer is unloaded from 9:00 a.m. to 12:00 p.m. with the driver and tractor remaining at the home to tour the museum dedicated to former Dallas Cowboys. The driver and vehicle then go to the carrier's Dallas terminal, located 45 miles from the Cowboys' facility, arriving at 1:00 p.m. to wait for further dispatch instructions. Total time for delivery =4 hours Total distance for delivery =45 miles Cost Analysis Using the equipment cost data and the distance traveled and time elapsed for the shipment, an approximate cost for this move can be calculated. This analysis can be seen in Table 4B-1. In a real costing situation, certain changes might need to be made to the cost data included in this example. Tractor fuel economy, for example, might need to be increased or maintenance cost per mile might need to be decreased. The cost analyst would need to determine the appropriate levels for each cost element, depending on the type of equipment and nature of the move. Pickup As can be seen in Table 4 B-1, the pickup operation generated seven types of costs. Depreciation expense per hour is calculated by: equipment cost/years depreciation/365/24 This formula gives the hourly cost for depreciation for both the tractor and the trailer. Interest expense (includes both principal plus interest) per hour can be calculated using any interest payment calculator. The appropriate formulas can be found in tables in any introductory finance text. Fuel cost per gallon and tractor fuel economy determine fuel cost per mile. This formula is: fuel cost per gallon/miles per gallon Labor, maintenance, insurance, and billing costs are given and are relatively easy to calculate. Total pickup costs for this move are $222.74. Line-haul Notice that the line-haul costs categories for this move are the same as for the pickup operation, except for the billing expense. This is simply because only one freight bill needs to be generated for this move. This will also be seen by the absence of a billing cost in the delivery section. Also, during the pickup operation, the driver was paid by the hour because waiting time was involved. In the line-haul section, the driver was paid by the mile. Obviously, pay scales for drivers will be determined by company or union policies. Other costs in the line-haul section are calculated in the same manner as they were in the pickup section. Obviously, however, the time and distance generated by the line-haul activity are used. Total line-haul costs for this move are \$1,986.22. Delivery The delivery activity generates the same type of costs as did the pickup activity, except for billing. Again, the time and distance associated with delivery need to be used in calculating costs. Costs for delivery are calculated in the same manner as they were in the pickup section. Total costs for delivery for this move are $155.50. Total Cost Adding the costs associated with pickup, line-haul, and delivery generates the total cost for this move of $2,364.46. Remember, however, that a 10 percent additional cost is added to make a contribution to the carrier's administration and overhead, so the total cost for this move is $2,600.91. TABLE 4B-1 Costing Example I. PICKUP Equipment Cost Data Equipment Purchase Price 1. Line-haul tractors =$120,000 2. Trailers =$40,000 ( 53 -foot dry van) Depreciation 1. Tractors =5-year straight line 2. Trailers =8-year straight line Interest 1. Tractors =6 percent APR for 5 years 2. Trailers =6 percent APR for 8 years Fuel 1. $3.83 per gallon for diesel 2. Line-haul tractors =6.0 miles per gallon Labor Cost 1. Line-haul drivers =$0.45 per mile 2. PUD operation drivers =$22.00 per hour Miscellaneous 1. Insurance cost =$0,067 per mile 2. Maintenance cost =$0.152 per mile 3. Billing cost =$1.95 per freight bill 4. Tractors and trailers are available for use 365 days, 24 hours per day 5. Administrative overhead cost =10 percent of total cost of move Route and Time of Move The shipment originates on June 2, 2017, from The Pennsylvania State University (located 35 miles from the carrier's dispatch/maintenance facility). A linehaul tractor and trailer are dispatched from the terminal at 7:30 a.m. (all times are Eastern Standard Time) and arrive at the shipper's dock at 8:30 a.m. The shipment is loaded from 8:30 a.m. to 12:00 p.m. Driver and tractor remain at Penn State during loading to visit the famous Nittany Lion statue. Driver and vehicle return to the carrier's terminal at 1:00 p.m. to pick up paperwork. Total time for pickup =5.5 hours Total distance for pickup =70 miles The vehicle and the driver depart from the terminal at 1:00pm. on the same day for Dallas, Texas. The driver operates from 1:00 p.m. to 11:00 p.m. and travels 450 miles. The driver rests from 11:00 p.m. to 7:00 a.m. (on June 3) in Knoxville, Tennessee, and then operates another 8 hours (7:00 a.m. to 3:00p.m.) and 375 miles, The driver rests again from 3:00 p.m. to 11:00 p.m. in Memphis, Tennessee. The driver concludes the trip by traveling 450 miles from 11:00 p.m. to 9:00a.m. (June 4) to the consignee in Dallas, the Dallas Cowboys' training facility. Total time for line-haul =44 hours or 1.83 days Total distance for line-haul =1,275 miles The trailer is unloaded from 9:00 a.m. to 12:00 p.m. with the driver and tractor remaining at the home to tour the museum dedicated to former Dallas Cowboys. The driver and vehicle then go to the carrier's Dallas terminal, located 45 miles from the Cowboys' facility, arriving at 1:00 p.m. to wait for further dispatch instructions. Total time for delivery =4 hours Total distance for delivery =45 miles Cost Analysis Using the equipment cost data and the distance traveled and time elapsed for the shipment, an approximate cost for this move can be calculated. This analysis can be seen in Table 4B-1. In a real costing situation, certain changes might need to be made to the cost data included in this example. Tractor fuel economy, for example, might need to be increased or maintenance cost per mile might need to be decreased. The cost analyst would need to determine the appropriate levels for each cost element, depending on the type of equipment and nature of the move. Pickup As can be seen in Table 4 B-1, the pickup operation generated seven types of costs. Depreciation expense per hour is calculated by: equipment cost/years depreciation/365/24 This formula gives the hourly cost for depreciation for both the tractor and the trailer. Interest expense (includes both principal plus interest) per hour can be calculated using any interest payment calculator. The appropriate formulas can be found in tables in any introductory finance text. Fuel cost per gallon and tractor fuel economy determine fuel cost per mile. This formula is: fuel cost per gallon/miles per gallon Labor, maintenance, insurance, and billing costs are given and are relatively easy to calculate. Total pickup costs for this move are $222.74. Line-haul Notice that the line-haul costs categories for this move are the same as for the pickup operation, except for the billing expense. This is simply because only one freight bill needs to be generated for this move. This will also be seen by the absence of a billing cost in the delivery section. Also, during the pickup operation, the driver was paid by the hour because waiting time was involved. In the line-haul section, the driver was paid by the mile. Obviously, pay scales for drivers will be determined by company or union policies. Other costs in the line-haul section are calculated in the same manner as they were in the pickup section. Obviously, however, the time and distance generated by the line-haul activity are used. Total line-haul costs for this move are \$1,986.22. Delivery The delivery activity generates the same type of costs as did the pickup activity, except for billing. Again, the time and distance associated with delivery need to be used in calculating costs. Costs for delivery are calculated in the same manner as they were in the pickup section. Total costs for delivery for this move are $155.50. Total Cost Adding the costs associated with pickup, line-haul, and delivery generates the total cost for this move of $2,364.46. Remember, however, that a 10 percent additional cost is added to make a contribution to the carrier's administration and overhead, so the total cost for this move is $2,600.91. TABLE 4B-1 Costing Example I. PICKUP