A 20-ft long non-uniform rod rest with its two ends on scales. When a 120-lb person stands at the geometric center of the rod, the left scale reads 220 lbs and the right end reads 300 lbs. Determine the distance from the rod's center-of-mass to the left scale. (a) 8 ft (b) 9 ft (c) 10 ft (d) 11 ft (e) 12 ft (f) None of the above.