4. A contractor is constructing a fill that will be used as the foundation for a concrete bus parking area. The plans for the parking area indicate a 1000 foot by 1000-foot surface for the 4-foot compacted fill. As per the specifications, the fill will be constructed in four 6-inch compacted lifts. The grader is equipped with a 12-foot blade and has a minimum turning radius of 22.5 feet. Three passes of the grader are required for each lift. The average grading speed is estimated to be 4 miles per hour. The effective grading width will be limited to about 75% of the length of the grader blade, and turns will be executed in first gear at an average speed of 1.5 mile per hour. The hourly ownership cost for the grader is estimated to be $25, the hourly operating cost is estimated to be $55, and the grader operator earns $60 per hour. (15 Points)

a. What is the estimated productivity of the grader in square yards per hour, if the contractor uses the looping method of grading and an operational efficiency of 45 minutes per hour?

b. How long will it take the grader to complete the grading for the foundation?

c. What is the estimated cost for grading per sq.ft, cost for grading in CCY.